Astronomy

Does another undetected planet languish in our Solar System’s distant reaches? Does it follow a distant orbit around the Sun in the murky realm of comets and other icy objects? For some researchers, the answer is “almost certainly.”

The case for Planet Nine (P9) goes back at least as far as 2016. In that year, astronomers Mike Brown and Konstantin Batygin published evidence pointing to its existence. Along with colleagues, they’ve published other work supporting P9 since then.

There’s lots of evidence for the existence of P9, but none of it has reached the threshold of definitive proof. The main evidence concerns the orbits of Extreme Trans-Neptunian Objects (ETNOs). They exhibit a peculiar clustering that indicates a massive object. P9 might be shepherding these objects along on their orbits.

This orbital diagram shows Planet Nine (lime green colour, labelled “P9”) and several extreme trans-Neptunian objects. Each background square is 100 AU across. Image Credit: By Tomruen – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=68955415

The names Brown and Batygin, both Caltech astronomers, come up often in regard to P9. Now, they’ve published another paper along with colleagues Alessandro Morbidelli and David Nesvorny, presenting more evidence supporting P9.

It’s titled “Generation of Low-Inclination, Neptune-Crossing TNOs by Planet Nine.” It’s published in The Astrophysical Journal Letters.

“The solar system’s distant reaches exhibit a wealth of anomalous dynamical structure, hinting at the presence of a yet-undetected, massive trans-Neptunian body—Planet Nine (P9),” the authors write. “Previous analyses have shown how orbital evolution induced by this object can explain the origins of a broad assortment of exotic orbits.”

To dig deeper into the issue, Batygin, Brown, Morbidelli, and Nesvorny examined Trans-Neptunian Objects (TNOs) with more conventional orbits. They carried out N-body simulations of these objects that included everything from the tug of giant planets and the Galactic Tide to passing stars.

29 objects in the Minor Planet Database have well-characterized orbits with a > 100 au, inclinations < 40°, and q (perihelia) < 30 au. Of those 29, 17 have well-quantified orbits. The researchers focused their simulations on these 17.

This figure from the research shows the 17 planets, their orbits, their perihelions, semi-major axes, and their inclinations. Image Credit: Batygin et al. 2024.

The researchers’ goal was to analyze these objects’ origins and determine if they could be used as a probe for P9. To accomplish this, they conducted two separate sets of simulations. One set with P9 in the Solar System and one set without.

The simulations began at t=300 million years, meaning 300 million years into the Solar System’s existence. At that time, “intrinsic dynamical evolution in the outer solar system is still in its infancy,” the authors explain, while enough time has passed for the Solar System’s birth cluster of stars to disperse and for the giant planets to have largely concluded their migrations. They ended up with about 2000 objects, or particles, in the simulation with perihelia greater than 30 au and semimajor axes between 100 and 5000 au. This ruled out all Neptune-crossing objects from the simulation’s starting conditions. “Importantly, this choice of initial conditions is inherently linked with the assumed orbit of P9,” they point out.

The figure below shows the evolution of some of the 2,000 objects in the simulations.

These panels show the evolution of selected particles within the calculations that attain nearly planar (i < 40°) Neptune-crossing orbits within the final 500 Myr of the integration. “Collectively, these examples indicate that P9-facilitated dynamics can naturally produce objects similar to those depicted in Figure 1” (the previous figure), the researchers explain. The top, middle, and bottom panels depict the time series of the semimajor axis, perihelion distance, and inclination, respectively. The rate of chaotic diffusion greatly increases when particles attain Neptune-crossing trajectories. Image Credit: Batygin et al. 2024.

These are interesting results, but the researchers point out that they in no way prove the existence of P9. These orbits could be generated by other things like the Galactic Tide. In their next step, they examined their perihelion distribution.

This figure from the research shows the perihelion distance for particles in a simulation with P9 (left) and without P9 (right.) The P9-free simulation shows a “rapid decline in perihelion distribution with decreasing q, as Neptune’s orbit forms a veritable dynamical barrier,” the researchers explain. Image Credit: Batygin et al. 2024.

“Accounting for observational biases, our results reveal that the orbital architecture of this group of objects aligns closely with the predictions of the P9-inclusive model,” the authors write. “In stark contrast, the P9-free scenario is statistically rejected at a ~5? confidence level.”

The authors point out that something other than P9 could be causing the orbital unruliness. The star was born in a cluster, and cluster dynamics could’ve set these objects on their unusual orbits before the cluster dispersed. A number of Earth-mass rogue planets could also be responsible, influencing the outer Solar System’s architecture for a few hundred million years before being removed somehow.

However, the authors chose their 17 TNOs for a reason. “Due to their low inclinations and perihelia, these objects experience rapid orbital chaos and have short dynamical lifetimes,” the authors write. That means that whatever is driving these objects into these orbits is ongoing and not a relic from the past.

An important result of this work is that it results in falsifiable predictions. And we may not have to wait long for the results to be tested. “Excitingly, the dynamics described here, along with all other lines of evidence for P9, will soon face a rigorous test with the operational commencement of the VRO (Vera Rubin Observatory),” the authors write.

A drone’s view of the Rubin Observatory under construction in 2023. The 8.4-meter is getting closer to completion and first light in 2025. The Observatory could provide answers to many outstanding issues, like the existence of Planet Nine. Image Credit: Rubin Observatory/NSF/AURA/A. Pizarro D

If P9 is real, what is it? It could be the core of a giant planet ejected during the Solar System’s early days. It could be a rogue planet that drifted through interstellar space until being caught up in our Solar System’s gravitational milieu. Or it could be a planet that formed on a distant orbit, and a passing star shepherded it into its eccentric orbit. If astronomers can confirm P9’s existence, the next question will be, ‘what is it?’

If you’re interested at all in how science operates, the case of P9 is very instructive. Eureka moments are few and far between in modern astronomy. Evidence mounts incrementally, accompanied by discussion and counterpoint. Objections are raised and inconsistencies pointed out, then methods are refined and thinking advances. What began as one over-arching question is broken down into smaller, more easily-answered ones.

But the big question dominates for now and likely will for a while longer: Is there a Planet Nine?

Stay tuned.

The post New Evidence for Our Solar System’s Ghost: Planet Nine appeared first on Universe Today.

What has one horn, two crewmates and shares a name with its ride into orbit? "Calypso," the plush sequined narwhal that is flying on the crew flight test of "Calypso," Boeing's CST-100 Starliner.

The star system GK Per is known to be associated

It’s that time again. NIAC (NASA Innovative Advanced Concepts) has announced six concepts that will receive funding and proceed to the second phase of development. This is always an interesting look at the technologies and missions that could come to fruition in the future.

The six chosen ones will each receive $600,000 in funding to pursue the ideas for the next two years. NASA expects each team to use the two years to address both technical and budgetary hurdles for their concepts. When this second phase comes to an end, some of the concepts could advance to the third stage.

“These diverse, science fiction-like concepts represent a fantastic class of Phase II studies,” said John Nelson, NIAC program executive at NASA Headquarters in Washington. “Our NIAC fellows never cease to amaze and inspire, and this class definitely gives NASA a lot to think about in terms of what’s possible in the future.”

Here they are.

Fluidic Telescope (FLUTE): Enabling the Next Generation of Large Space Observatories

Telescopes are built around mirrors and lenses, whether they’re ground-based or space-based. The JWST’s large mirror is 6.5 meters in diameter but had to be folded up to fit inside the rocket that launched it and then unfolded in space. That’s a tricky engineering feat. Engineers are building larger and larger ground-based telescopes, too, and they’re equally tricky to design and build. Could FLUTE change this?

FLUTE envisions lenses made of fluid, and the FLUTE team’s concept describes a space telescope with a primary mirror 50 meters (164 ft.) in diameter. Creating glass lenses for a telescope this large isn’t realistic. “Using current technologies, scaling up space telescopes to apertures larger than approximately 33 feet (10 meters) in diameter does not appear economically viable,” the FLUTE website states.

But in the microgravity of space, fluids behave in an intriguing way. Surface tension holds liquids together at their surfaces. We can see this on Earth, where some insects use surface tension to glide along the surfaces of ponds and other bodies of water. Also, on Earth, surface tension holds small drops of water together. But in space, away from Earth’s dominating gravity, surface tension is much more effective. There, water maintains the most energy efficient shape there is: a sphere.

Another force governs water: adhesion. Adhesion causes liquids to cling to surfaces. In the microgravity of space, adhesion can bind liquid to a circular, ring-like frame. Then, due to surface tension, the liquid will naturally adopt a spherical shape. If the liquid can be made to bulge inward rather than outward, and if the liquid is reflective enough, it creates a telescope mirror.

The FLUTE team would like to make optical components in space. The liquid would stay in the liquid state and form an extremely smooth light-collecting surface. As a bonus, FLUTE would also self-repair after any micrometeorite strike.

The FLUTE study is led by Edward Balaban from NASA’s Ames Research Center in California’s Silicon Valley. The FLUTE team has already done some tests on the ISS and on zero-g flights.

FLUTE researchers experience microgravity aboard Zero Gravity Corporation’s G-FORCE ONE aircraft while operating an experiment payload during a series of parabolic flights. Image Credits: Zero Gravity Corporation/Steve Boxall

Pulsed Plasma Rocket (PPR): Shielded, Fast Transits for Humans to Mars

It takes too long to get to Mars. It’s a six-month journey each way, plus time spent on the surface. All that time in microgravity, exposure to radiation, and other challenges make the trip very difficult for astronauts. PPR aims to fix that.

PPR isn’t a launch vehicle for escaping Earth’s gravity well. It would be launched on a heavy lift vehicle like SLS and then sent on its way.

PPR was originally derived from the Pulsed Fission Fusion concept. But it’s more affordable, and also smaller and simpler. PPR might generate 100,000 N of thrust with a specific impulse (Isp) of 5,000 seconds. Those are good numbers. PPR could reduce the travel time to Mars to two months.

It has other benefits as well. It could propel larger spacecraft to Mars on trips longer than two months, carrying more cargo and also provide heavier shielding against cosmic rays. “The PPR enables a whole new era in space exploration,” the team writes.

PPR is basically a fusion system ignited by fission. It’s similar to a thermonuclear weapon. But rather than a run-away explosion, the combined energy is directed through a magnetic nozzle to produce thrust.

In phase two, the PPR team intends to optimize the engine design to produce more specific impulse, perform proof-of-concept experiments for major components, and design a shielded ship for human missions to Mars.

This study is led by Brianna Clements with Howe Industries in Scottsdale, Arizona.

The Great Observatory for Long Wavelengths (GO-LoW)

One of modern astronomy’s last frontiers is the low-frequency radio sky. Earth’s ionosphere blocks our ground-based telescopes from seeing it. And space-based telescopes can’t see it either. It’s because the wavelengths are so long, in the meter to the kilometre scale. Only extremely massive telescopes could see these waves clearly.

GO-LoW is a potential solution. It’s a space-based array of thousands of identical Small-Sats arranged as an interferometer. It would sit at an Earth-Sun Lagrange point and observe exoplanet and stellar magnetic fields. Exoplanet magnetic fields emit radio waves between 100 kHz and 15 MHz. The GO-LoW team says their interferometer could perform the first survey of exoplanetary magnetic fields within 5 parsecs (16 light years.) Magnetic fields tell scientists a lot about an exoplanet, its evolution, and its processes.

GO-LoW is a Great Observatory concept to open the last unexplored window of the electromagnetic (EM) spectrum. The Earth’s ionosphere becomes opaque at approximately 10m wavelengths, so GO-LoW will join Great Observatories like HST and JWST in space to access this spectral window. Image Credits: NASA/GO-LoW

While there’s no doubt that large telescopes like the JWST are powerful and effective, they’re extremely complex and expensive. And if something goes wrong with a critical component, the mission could end.

GO-LoW takes a different approach. By using thousands of individual satellites, the system is more resilient. GO-LoW would have a hybrid constellation. Some of the satellites would be smaller and simpler satellites called “listener nodes” (LN,) while a smaller number of them would be “communication and computation” nodes (CCNs). They would collect data from the LNs, process it, and beam it back to Earth.

The GO-LoW says it would only take a few heavy launches to place an entire 100,000 satellite constellation in space.

The technology for the SmallSats already exists. The challenge the GO-LoW team will address with their phase two funding is developing a system that will harness everything together effectively. “The coordination of all these physical elements, data products, and communications systems is novel and challenging, especially at scale,” they write.

GO-LoW is led by Mary Knapp with MIT in Cambridge, Massachusetts.

Radioisotope Thermoradiative Cell Power Generator

It’s sort of like solar power in reverse.

The RTCPG is a power source for spacecraft visiting the outer planets. They promise smaller, more efficient power generation for smaller science and exploration missions that can’t carry a solar power system or nuclear power system. Both those systems are bulky, and solar power is limited the further away from the sun a spacecraft goes.

The thermoradiative cell (TRC) uses radioisotopes to create heat as an MMRTG does. But the TRC uses the heat to generate infrared light which generates electricity. In initial testing, the system generated 4.5 times more power from the same amount of PU-238.

Much of phase two’s work will involve materials. “Metal-semiconductor contacts capable of surviving the required elevated temperatures will be investigated,” the team explains. The team developed a special cryostat testing apparatus in phase one.

“Building on our results from Phase I, we believe there is much more potential to unlock here,” the team writes.

This power generation concept study is from Stephen Polly at the Rochester Institute of Technology in New York.

FLOAT: Flexible Levitation on a Track

What if Artemis is enormously successful? How will astronauts move their equipment around the lunar surface efficiently?

If the team behind FLOAT has their way, they’ll build the Moon’s first railway. Sort of. This artist’s concept shows a possible future mission depicting the lunar surface with planet Earth on the horizon. Image Credit: Ethan Schaler

FLOAT would provide autonomous transportation for payloads on the Moon. “A durable, long-life robotic transport system will be critical to the daily operations of a sustainable lunar base in the 2030’s,” the FLOAT team writes.

The heart of FLOAT is a three-layer flexible track that’s unrolled into position without major construction. It consists of three layers: a graphite layer, a flex-circuit layer, and a solar panel layer.

The graphite layer allows robots to use diamagnetic levitation to float over the track. The flex-circuit layer supplies the thrust that moves them, and the thin-film solar panel layer generates electricity for a lunar base when it’s in sunlight.

The system can be used to move regolith around for in-situ resource utilization and to transport payloads around a lunar base, for example, from landing zones to habitats.

“Individual FLOAT robots will be able to transport payloads of varying shape/size (>30 kg/m^2) at useful speeds (>0.5m/s), and a large-scale FLOAT system will be capable of moving up to 100,000s kg of regolith/payload multiple kilometres per day,” the FLOAT team explains.

With their phase two funding, the FLOAT team intends to design, build, and test scaled-down versions of FLOAT robots and track. Then, they’ll test their system in a lunar analog testbed. They’ll also test environmental effects on the system and how they alter the system’s performance and longevity.

Ethan Schaler leads FLOAT at NASA’s Jet Propulsion Laboratory in Southern California.

SCOPE: ScienceCraft for Outer Planet Exploration

Some of the most intriguing planets and moons in the Solar System are well beyond Jupiter. But exploring them is challenging. Extremely long travel times, restrictive mission windows, and large expenses limit our exploration. But SCOPE aims to address these limitations.

Typically, a spacecraft carries a propulsion and power system along with its instruments and communication systems. NASA’s Juno mission to Jupiter, for example, carries a chemical rocket engine for propulsion, 50 square meters of solar panels, and 10 science instruments. The solar panels alone weigh 340 kg (750 lbs.) Juno is powerful, produces a wide variety of quality science data, and is expensive.

ScienceCraft takes a different approach. It combines a single science instrument and spacecraft into one monolithic structure. It’s basically a solar sail with a built-in spectrometer. They’re aiming their design at the Neptune-Triton system.

This artist’s depiction shows ScienceCraft, which integrates the science instrument with the spacecraft by printing a quantum dot spectrometer directly on the solar sail to form a monolithic, lightweight structure.
Image Credit: Mahmooda Sultana

“By printing an ultra-lightweight quantum dot-based spectrometer, developed by the PI Sultana, directly on the solar sail, we create a breakthrough spacecraft architecture allowing an unprecedented parallelism and throughput of data collection and rapid travel across the solar system,” the ScienceCraft team writes.

Instead of merely providing the propulsion, the sail doubles as the spacecraft’s science instrument. The small mass means that ScienceCraft could be carried into orbit as a secondary payload. The team says they’ll use phase two to identify and develop key technologies for the spacecraft and to further mature the mission concept. They say that because of the low cost and simplicity, they could be ready by 2045.

“By leveraging these benefits, we propose a mission concept to Triton, a unique planetary body in our solar system, within the short window that closes around 2045 to answer compelling science questions about Triton’s atmosphere, ionosphere, plumes and internal structure,” the ScienceCraft team explains.

ScienceCraft is led by NASA’s Mahmooda Sultana at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.

The post NASA Takes Six Advanced Tech Concepts to Phase II appeared first on Universe Today.

It’s time to begin a new mini-series, where we’ll look at different classes of galaxies. Today, we’ll start with the dwarf galaxies, which flock around larger galaxies like the Milky Way. Are they the building blocks for modern structures?

Transcript

(This is an automatically generated transcript)

Fraser Cain [00:01:19] Astronomy cast. Episode 718 The Galaxy series: Dwarfs. Welcome to Astronomy Cast, our weekly fact space during through the cosmos, where we help you understand not only what we know, but how we know what we know. I’m Fraser Cain, I’m the publisher of Universe Today. With me, as always, is Doctor Pamela Gay, a senior scientist for the Planetary Science Institute and the director of CosmoQuest. Hey, Pamela. How are you doing?

Pamela Gay [00:01:40] I am doing okay enough. I am recovering from discovering shampoo I am terribly allergic to. I’m so sorry there was chaos on our normal recording day, and I continue to be in a bit of a Benadryl haze, but I’m better than it was yesterday. So thank you, everyone, for your patience.

Fraser Cain [00:02:02] All right. Well, hopefully you’ll be here cognizant and ready to explain galaxies. Now, I did one of my live streams last night, and I was talking about different kinds of telescopes, blah, blah, blah. And I always recommend first thing you do is you get a pair of binoculars and there’s like a sale on for Celestron Sky Masters. So, the 20mm x 80mm’s are down from $200 U.S to $140 U.S on Amazon. Wow.

Pamela Gay [00:02:32] Yes like 50%.

Fraser Cain [00:02:33] Yeah almost. And then similar for the 25mm x 70mm. And so I’m not sure what the story is. There’s no ad. This is not. We’re not sponsored – I just noticed this. And so if anyone’s like “oh I really want to pick up a pair of astronomical binoculars.” … I don’t know if the sale will last. But they seem to be relatively inexpensive on Amazon in the US, that is. That is the beginning and the end of this message.

It’s time to begin a new mini series where we’ll look at different classes of galaxies. And today we’re going to start with the dwarf galaxies, which flock around the larger galaxies like the Milky Way. Are they the building blocks for the modern structures that we see all around us? So, give me an example of a dwarf galaxy that maybe people in the southern hemisphere are familiar with. Give me two.

Pamela Gay [00:03:25] In the southern hemisphere, they have the Large and Small Magellanic Clouds. These are dwarf galaxies that look like someone grabbed a handful of the plane in the Milky Way and just tossed it to the side. These are two systems where it’s not entirely understood. And there is debate in the literature over whether or not they’re going to end up in orbit around our Milky Way, whether or not they’re going to end up flying past. Yeah. And I feel like every few years they change their mind. Right.

Fraser Cain [00:03:55] It’s like the question of whether or not the sun is going to consume the Earth. Yeah. We get we get that going back and forth as well. But it’s only like give us a comparison. Like how big and massive is a dwarf galaxy compared to something like the Milky Way?

Pamela Gay [00:04:13] They can get so tiny. So we have systems like the Ursa minor dwarf toroidal galaxy, which is one of the smaller ones that are the size of globular clusters. They have masses of hundreds of thousands of stars. Majority of that is actually dark matter. And then they get up to being fractions, like a few percent. 10%.

Fraser Cain [00:04:40] Yeah, yeah, yeah.

Pamela Gay [00:04:42] Of of the size of, of a spiral galaxy like us. Now, to be clear, the Large Magellanic Cloud is. A dwarf spiral barred according to the latest classifications. Right. So so I feel like there’s folks that are going to be adding are saying but I have heard it’s it’s still a dwarf, folks. It’s still a dwarf.

Fraser Cain [00:05:10] It’s a jumbo shrimp.

Pamela Gay [00:05:11] Yes.

Fraser Cain [00:05:12] Exactly right. So okay. And then a apart from the, the LMC, structurally, what do these dwarf galaxies tend to look like in terms of, like, regular matter? Stars got dark gas dust and dark matter.

Pamela Gay [00:05:31] So they’re there are basically the smallest ones that are dark matter dominated and have globular cluster ish like masses. And then there are the larger ones, which were able to undergo multiple generations of star formation and have normal to low amounts of dark matter. So just like low luminosity galaxies can have squirrely amounts of dark matter, dwarf galaxies can have squirrely amounts of dark matter. And there’s lots of debate about how this ends up being the case. The story that seems to be coming together in the literature is that on the small side of this, you have that first generation of supernovae that goes off, and it is able to blast large amounts of the baryonic matter out of the halo, of these dwarf galaxies, when you start looking at them, in molecular lines, you see lots of cold gas outside the system’s core, and their dark matter dominated. So this seems to communicate that through supernovae and other actions, they blast out most of their luminous matter, most of their baryonic matter. Some of that gets blasted out at escape velocities. And what’s left behind is essentially a halo of dark matter hanging out darkly in in the halo of a galaxy.

Fraser Cain [00:07:01] So it’s kind of like a star, which, you know, or a stellar nebula. When it starts to finally form in, the stars start to turn on, and then they their stellar winds blow and they clear out all that gas and dust. There’s these three body interactions with stars whipping around each other, but in a large galaxy like the Milky Way, because the gravity is so intense, the escape velocity is very high. And so these stars are stuck. They’re just not near the cluster. They escape the velocity, they escape the cluster, but they don’t escape the galaxy. But I guess in these dwarf galaxies, there’s so little gravity holding the thing together that it can shed bits and pieces of itself out into space quite easily.

Pamela Gay [00:07:43] And this gets people asking questions along the lines of what is the difference between a small dwarf galaxy and a globular cluster? And it appears to be one strictly of of how they’re formed, where we’re now starting to understand that globular clusters most likely formed during galaxy interactions, where material gets slammed together and where these shockwaves come together, you get globular clusters forming, whereas dwarf galaxies form kind of like an open cluster writ large. You have this massive cloud of material that collapses under its own gravity. And as it does this, it’s it’s able to start having star formation. And so you have a dark matter halo. Luminous material gravitationally pulls into the center star formation. And supernovae can blast material out if it’s too small. Multiple generations of star formation can go on and it’s large enough. And, yeah, they’re just cool little systems.

Fraser Cain [00:08:51] Like with the Large Magellanic Cloud, though, the largest regions of star formation that we know of in our near vicinity are in that galaxy or in that dwarf galaxy, like there are like we think about the Tarantula Nebula. It’s a ludicrous amount of star formation stars vastly more massive than anything we know of in the Milky Way. So is that just a special case or. It is.

Pamela Gay [00:09:14] It’s big.

Fraser Cain [00:09:15] It’s big. Yeah.

Pamela Gay [00:09:16] This this is where we start getting into the jumbo shrimp category.

Fraser Cain [00:09:20] And it gets to tidal interactions too with the Milky Way.

Pamela Gay [00:09:23] Well, so you have a number of different things going on. This is a system that has its own globular clusters that is indeed interacting with the galaxy, our galaxy. There are occasional questions of were the Large and Small Magellanic Cloud wants the same thing? I don’t think that’s ever come to a consensus, but the question does get asked, which amuses me. And with all of these different interactions going on. Interactions. Trigger shockwaves trigger star formation. And so, as the system sweeps past the Milky Way as it interacts with our dark matter halo, as it starts to interact with our outermost, actual starts the baryonic stuffs. You’re getting shocks, the trigger star formation. And it’s glorious to look at.

Fraser Cain [00:10:15] Yeah, yeah. So then let’s talk about, like, where these things came from. Do we know where do or how dwarf galaxies originate? Because I’m, I’m sort of thinking about, say, a star cluster where you’ve got this giant stellar nebula like the Orion Nebula, and you’ve got concentrations of larger amounts with larger stars forming, and then you’ve got smaller areas and maybe you’re even getting these rogue planets forming. And so when we think about the primordial hydrogen and helium in the early universe, is it the same idea as a stellar nebula writ large, with large blobs turning into certain sized galaxies and smaller blobs turning into, you know, the the galaxy equivalent of red dwarf stars.

Pamela Gay [00:11:02] So so I. I’m just going to clean up the language here a little bit. So we have. You know, like blubber. No that’s fine. I’m down with blubber.

Fraser Cain [00:11:11] So. All right, all right.

Pamela Gay [00:11:13] Solar nebulae generally form to solar systems forming. We have star forming regions, which are a kind of nebula. I’m not sure what you’re referring to with a stellar nebula.

Fraser Cain [00:11:28] So a sort of star forming region like the Orion Nebula, where you’ve got this giant area of gas and dust of different concentrations and different stars whirling up inside this whole region of different masses. You know, there is this there is this mass relationship. Across the, you know, in a in a star forming region that creates. Stars of different sizes is of the same mechanism to make bigger galaxies versus dwarf galaxies.

Pamela Gay [00:11:57] No, because star forming regions are singular clouds that have been shocked into simultaneously forming all of these stars. And. You can have dwarf galaxies like Ursa minor, where all of the gas in them. I got shocked into a single star forming burst and whatever wasn’t used up got blasted away. But they didn’t form that way. They formed. We think that the modern dwarf, irregulars that are rich in star formation are actually analogs to these dwarf blue galaxies that we’re starting to see in images, where we’re seeing the smallest of the dark matter halos that formed are pulling in material. And that material, just like in any form in galaxy, has the chance to then clump up. And some of those clumps are going to form stars now, some form later. And. In the case of the dwarfs, there’s just not that much material. So you don’t tend to get the same numbers of star forming epics that you get with bigger systems. But it’s that same dark matter. Halo collects material inside material forms, galaxies, and these are essentially building blocks of large galaxies that came later.

Fraser Cain [00:13:23] Right, right. But I guess let me try and kind of rephrase the question, because I sort of I’m imagining in the beginning there is just the primordial hydrogen and helium. There is the dark matter. Yeah. Structure that that underlies the whole thing. And you’ve got different concentrations based on regions of over under density in the, in the original universe. And then gravity is pulling things together, pulling. And so places where you’ve got an over density, you’ve got more stuff being pulled together in places you’ve got an under density, you’ve got less of being pulled together. And after a while, like pizza dough that’s being pulled too thin, you start to get gaps opening up, voids opening up, and then the, you know, as you pull far farther and farther, then these things kind of snap and the gravity pulls them together into however much gas you have. And then the expansion continues. And so now you’re left with this just distribution of blob. I’m gonna go back to my blob of material that is now like gravitationally distinct from the other ones, as they’re sort of, you know, they’re still orbiting one another, but they are not continuing to merge up into larger objects in the beginning. That roughly on the right track then. And so the dwarf galaxies are like are the dwarf galaxies that we see today. The result of those sheared off chunks of primordial material. Or was there some mechanism later on that spun them out that that split them in half into smaller pieces?

Pamela Gay [00:15:09] So things don’t get split up later. Generally, unless it’s like a title tale or something. And those probably aren’t forming dwarf galaxies.

Fraser Cain [00:15:17] Right?

Pamela Gay [00:15:18] So the way to think about it is things tend to break up into pieces in a distribution. If you drop a mug, you’re going to get a distribution of pieces where you’ll have a few giant pieces, and then inevitably, a whole lot of little tiny crumbs, which is always the source of sadness when trying to reassemble the mugs powder.

Fraser Cain [00:15:40] Yeah, right.

Pamela Gay [00:15:42] And when the early universe fragmented, we had a distribution of of blobs of material going back to your blobs. And there were a few that were giant. And these were those first forming giant galaxies.

Fraser Cain [00:16:01] Right.

Pamela Gay [00:16:02] But the majority were these little tiny lumps of extra material that pulled in stuff, and then those within them could fragment further. So you have all this stuff is gravitationally bound together, but within this gravitationally bound together, you could get further fragmenting into star forming regions that would start up stars at different points, different times, due to what triggers were there to start the star formation. So entire universe has swept over and under densities. It fragments into pieces. Big pieces formed giant galaxies. The majority is little pieces from little galaxies that are gravitationally bound. And within that gravitationally bound, you could get further collapse into star forming regions.

Fraser Cain [00:16:56] So I mean, we thanks to Gaia, the amazing guy emission, we can see the evidence of the dwarf galaxies that the Milky Way has consumed in the ancient past.

Pamela Gay [00:17:09] And and we’re still eating a very hungry galaxy. Sure.

Fraser Cain [00:17:15] But it is interesting that a lot of the larger mergers, like, I think the last great merger happened like 8 billion years ago. Yeah. So so you say it’s happening now, but it sounds like it was furious in the early universe. And now it’s a lot less common as as the universe matures into a, into a old age. But how what contribution? Because it’s all right. Like, one of the big questions that that Webb was designed to ask was, will we see these dwarf galaxies coming together as building blocks of the larger galaxies? That is, those observations are now happening. What is this story that we’re seeing of galactic evolution over the entire age of the universe?

Pamela Gay [00:18:04] We’re still figuring out all the details. What we do see is there are these small, bright blue, furious. First, start with star formation galaxies in the early universe. Just finding them. What we see is there are galaxies that are undergoing greater amounts of merger activity in the past. There are more quasars in the past. And that excess material to feed black holes that, significantly more galaxy merger is going on the past. What is happening is over time, gravity is pulling things into tighter and tighter structures. So we went from lots and lots of small stuff to the small stuff. Having time to consume one another, to building bigger things, then kept eating the smaller things. And so we have this picture where some galaxies did just form giant from day zero. But the majority of systems grew through the constant merger of larger and larger systems. And the shapes of the galaxies seem to be dominated by what were the angles that they came together? What were the eye? Basically the distribution of big thing to small things orbiting it for grand spirals. So a lot of these grand design spiral galaxies that we see are driven by having a smaller companion. So here we can think dwarf galaxies in many cases for bringing us grand designs, spiral galaxies. Through this constant merger of systems we get bigger and bigger things. And this is an ongoing process. We continue to eat dwarf galaxies in lower numbers because we’ve already ate so many of them. There’s just not as many left to be eaten.

Fraser Cain [00:20:02] Right?

Pamela Gay [00:20:03] We continue to eat them. And then we’re also seeing the larger systems merging together. And and this is where things get more and more interesting as time progresses, because we’re going to run out of things to merge eventually. Right. And and so it’s, it’s small galaxies merging bigger and bigger all the way down.

Fraser Cain [00:20:25] I mean, I think there’s sort of like two pathways that’s there’s really interesting things to do with T. And the first one is this idea, you know, they’re called the impossible galaxies, but they just, you know, they’re not impossible. They’re possible. But the gist is that we’ve got these big galaxies early on in the universe. You’re seeing quasars at less than a billion years after the Big Bang. You’re seeing spiral galaxies again as literally within, you know, the first billion years of the universe. And so that is definitely pushing things back to what you mentioned, that you get large chunks are just turning directly into big galaxies. And and then also this history, thanks to guy of seeing when the mergers happened that that a lot of the big mergers happened early on in the Milky Way’s history. And that’s just driven by these dwarf galaxies. And so what do you know? It’s more complicated than we thought, that it’s probably both right, that you’re getting the dwarf galaxies being the building blocks of the galaxies. And a lot of them are just never making it close to another galaxy and are remaining unperturbed since almost the beginning of the universe.

Pamela Gay [00:21:35] And the difficult thing is, they are hard to see. And when the smaller things are the most numerous and the smallest things tend to be the most dark matter dominated, it becomes very difficult to do a census of these beyond our own local group. We know dwarf galaxies dominate. We know that galaxies, large ones, participate in dwarf tossing using their gravity on a regular basis.

Fraser Cain [00:22:02] Right.

Pamela Gay [00:22:03] And and so this is the hardest to observe kind of galaxy. And also the most common and also the most necessary to understand what I love is as we try and understand our past, different things that we’ve known for a long time, like the other half classifications of galaxy clusters where half of them not half, but a lot of them are going in entirely the wrong direction. And we have this thick disk to our galaxy that has a slightly different metal composition. That is all getting tracked back to eating larger dwarf galaxies and consuming their their globular clusters consuming their matter. We are a system made from multiple galaxies coming together and sharing their material and their angular momentum and everything else to give us this barred spiral structure. And that bar is due to our companions.

Fraser Cain [00:23:02] Right? Yeah. Now, you talked about sort of how some of these galaxies are dark matter dominated. Yes. In other cases it’s the opposite. They have very little dark matter. So what is the mechanism that is creating such vast differences in composition for these different dwarf galaxies?

Pamela Gay [00:23:23] It likely comes down to different interactions. This is what we’re also finding with the low surface luminosity galaxies, where if you have a system that or two systems that pass through each other, you can end up with the dark matter staying in one part and some of the luminous matter escaping. And so you get systems that are luminous matter dominated, you get systems that are dark matter dominated. And of course, the Holy Grail is finding the system that is just dark matter. We haven’t quite got there yet. We’re getting close with some of these systems. Yeah. They’re the the luminous to dark matter ratio is in the hundreds with some galaxies. And this is where it starts to get necessary to look in every wavelength to find. All right. Is there just super cold gas in these systems that is giving the mass that we don’t otherwise see? Because cold mass is. Is transparent and not exactly luminous and optical. So millimeter dishes are so important for studying these, getting down, looking for the molecules and. They’re cool and hard to see and don’t get the attention they deserve, because they’re not necessarily the kind of thing you write press releases with pretty pictures about. Yeah.

Fraser Cain [00:24:54] It is amazing to me how often new dwarf galaxies are being discovered, that every year or so, I feel like there’s a couple of new dwarf galaxies that turn up from larger and larger surveys of our neighborhood. And some of these ones, as you said, that are, you know, are dark matter dominated, are harder to find. And so often it’s like gravitational lensing gives us insights into where these things are. And I know and you mentioned early on there’s like one that, as you said, has the mass of a star cluster.

Pamela Gay [00:25:28] Yeah. There’s several like that. Yeah.

Fraser Cain [00:25:30] And yet is a is a galaxy with all the parts and pieces.

Pamela Gay [00:25:36] The Ursa minor dwarf squirrel galaxy is near and dear to me. It was the topic of my master’s thesis.

Fraser Cain [00:25:41] Yeah.

Pamela Gay [00:25:41] If you take an image of it and it’s about a degree across. So you need a big field of view. You can’t tell you’re seeing a galaxy. It’s just an over density of stars in the sky. And it’s closer to us than some of our globular clusters. So these are large diffuse systems where you can see individual stars and look right through them to galaxies beyond. They’re super cool.

Fraser Cain [00:26:08] I’m looking at. There’s like since when you did your doctoral thesis, there have been many more. Even lighter. Even smaller.

Pamela Gay [00:26:17] Oh, yeah.

Fraser Cain [00:26:18] Galaxies. It’s it’s kind of amazing. So for example, is one called SEG two that has about a thousand stars. Yeah. That’s it. A thousand stars in a galaxy.

Pamela Gay [00:26:28] Yeah.

Fraser Cain [00:26:29] So again, this is the scale of of what’s out there. And yet the galaxy itself has about 55,000 times the mass of the sun. And so.

Pamela Gay [00:26:41] 1000 matter that.

Fraser Cain [00:26:42] Dark dark matter dominated. Yeah. Exactly. Right. That is that is causing the bulk of that of the mass of that galaxy. It’s fascinating. And. I wish they were easier to see because they are telling the true story of the history of the universe. And this is what Webb. One of the things Webb was really designed to do was to find these things and see them coming together, to really tell us that story of where we came from. And if there couldn’t be a more cutting edge piece of research right now that, you know, we look back and we think, oh, what are the things that changed dramatically? I’ll bet you the story of dwarf galaxies will be one of the ones that we’re going to come back to in ten years and go, oh, we didn’t know anything about galaxies. And thanks to thanks to all of these, like Euclid and Vera Rubin and Nancy Grace Roman and, the Desy database, because all these things that are coming online to search for dark matter, dark energy, and to do these detailed galaxy surveys of the area around us. And I think our our understanding of the universe is going to change subtly or dramatically in the coming years. And so don’t be surprised if we like dwarf galaxies. We hardly knew you.

Pamela Gay [00:28:02] And what’s amazing is what is nearly invisible today, because they’re made of elder red stars.

Fraser Cain [00:28:08] Yeah.

Pamela Gay [00:28:09] They shone like fireflies in the early universe. These were rich in blue stars billions of years ago, and so how our universe looks has radically changed with the single epic of star formation dying out in all these systems. So they were the bright blue galaxies of the past, and they’re the red, almost impossible to see galaxies of today.

Fraser Cain [00:28:35] All right. So stay tuned to this series. We will be back next week with the next episode. Thanks, Pamela.

Pamela Gay [00:28:42] Thank you, Fraser, and thank you to everyone out there who is donating at the $10 a week or higher level. Thank you, actually, to everyone that donates. I just want to be clear, we are grateful for all of you, but I only mispronounce the names of folks donating at the $10 or higher level. This week I’m going to tempt and fail to pronounce the following people who I am grateful for as names. Thank you to Paul L Hayden, Steven Coffee, Bart Flaherty, Benjamin Carrier, and 1961 super symmetrical Michael Purcell. Jim Schooler share some Andrew Stevenson, Tim McCormack, and the lonely stand person Kenneth Ryan, Gregory Singleton, Frodo Tenham Bo, Michael Regan, father Prax J. Alex Anderson, Glenn McDavid, Jim McGinn, Bruce Amazing, Szymanski, planetary, the air major Michael York, Matthew Horstman, Scott. Cohen, Scott. Bieber, Georgie. Ivanov, Justin. Proctor, Matthias. Hayden, Lu Zealand, Nyla the big squish squash David Gates, Benjamin. Mueller. Cooper, Eran. Zagreb, beta. Peter Philip Grant, Grand Don. Mondesi, James. Raj. Roger. Wow. That one I shouldn’t have to stumble over but I’m going to today. It’s a that’s. Yeah, it is. Shawn. Max, Cami Raspbian, Nate Detweiler, Sam Brooks and his mom and Dean, thank you all so very much. You make this show possible.

Fraser Cain [00:30:18] Thanks, everyone. And we’ll see you next week.

Pamela Gay [00:30:21] Bye bye. Astronomy cast is a joint product of Universe Today and the Planetary Science Institute. Astronomy cast is released under a Creative Commons Attribution license. So love it, share it, and remix it, but please credit it to our hosts, Fraser Cain and Doctor Pamela Gay. You can get more information on today’s show topic on our website. Astronomy. Cars.com. This episode was brought to you thanks to our generous patrons on Patreon. If you want to help keep the show going, please consider joining our community at Patreon.com Slash Astronomy Cast. Not only do you help us pay our producers a fair wage, you will also get special access to content right in your inbox and invites to online events. We are so grateful to all of you who have joined our Patreon community already. Anyways, keep looking up. This has been Astronomy Cast.

Two asteroids are expected to make close but safe approaches to Earth this week, and you can watch them live.

The video gives an insight into the energetic events that transfer energy and plasma into the solar corona that ultimately drives the solar wind.

NASA and Boeing are working together to send the first astronauts to space on Starliner on May 6. Among the Mission Control support team is Kennedy Space Center's chief engineer.

During a mission dress rehearsal, NASA’s Boeing Crew Flight Test astronaut Suni Williams flashes a thumbs up in her Boeing spacesuit inside the crew suit-up room inside the Neil A. Armstrong Operations and Checkout Building at the agency’s Kennedy Space Center in Florida on Friday, April 26, 2024. As part of the agency’s Commercial Crew Program, Williams and fellow NASA astronaut Butch Wilmore are the first to launch to the International Space Station aboard Boeing’s Starliner spacecraft. Liftoff atop a United Launch Alliance Atlas V rocket from Space Launch Complex-41 at nearby Cape Canaveral Space Force Station is scheduled for 10:34 p.m. ET Monday, May 6.

On Friday, May 3rd, the sixth mission in the Chinese Lunar Exploration Program (Chang’e-6) launched from the Wenchang Spacecraft Launch Site in southern China. Shortly after, China announced that the spacecraft separated successfully from its Long March 5 Y8 rocket. The mission, consisting of an orbiter and lander element, is now on its way to the Moon and will arrive there in a few weeks. By June, the lander element will touch down on the far side of the Moon, where it will gather about 2 kg (4.4 lbs) of rock and soil samples for return to Earth.

The mission launched four years after its predecessor, Chang’e-5, became China’s first sample-return mission to reach the Moon. It was also the first lunar sample return mission since the Soviet Luna 24 mission landed in Mare Crisium (the Sea of Crisis) in 1976. Compared to its predecessor, the Chang’e-6 mission weighs an additional 100 kg (220 lbs), making it the heaviest probe launched by the Chinese space program. The surface elements also face lesser-known terrain on the far side of the Moon and require a relay satellite for communications.

Speaking of surface elements, the China Academy of Space Technology (CAST) has since released images showing how the mission also carries a rover element. This payload was not part of mission data disclosed by China before the flight. But as SpaceNews’ Andrew Jones pointed out, the rover can be seen in the CAST images (see above) integrated onto the side of the lander.

Yeah, okay. That looks like a previously undisclosed mini rover on the side of the Chang'e-6 lander lol. Via CAST: https://t.co/gS0Jy5L9hw pic.twitter.com/9vvTnribpl

— Andrew Jones (@AJ_FI) May 3, 2024

“Little is known about the rover, but a mention of a Chang’e-6 rover is made in a post from the Shanghai Institute of Ceramics (SIC) under the Chinese Academy of Sciences (CAS),” he wrote. “It suggests the small vehicle carries an infrared imaging spectrometer.” This rover is no doubt intended to assist the lander with investigating resources on the far side of the Moon. This is consistent with China’s long-term plans for building the International Lunar Research Station (ILRS) around the southern polar region in collaboration with Roscosmos and other international patterns.

Similar to NASA’s plans for the Lunar Gateway and Artemis Base Camp, this requires that building sites be selected near sources of water ice and building materials (silica and other minerals). Ge Ping, the deputy director of the Center of Lunar Exploration and Space Engineering (CLESE) with the China National Space Administration (CNSA), related the importance of the sample-return mission to CGTN (a state-owned media company) before the launch:

“The Aitken Basin is one of the three major terrains on the Moon and has significant scientific value. Finding and collecting samples from different regions and ages of the Moon is crucial for our understanding of it. These would further study of the moon’s origin and its evolutionary history.”

In addition, the Chang’e-6 orbiter carries four international payloads and satellites including a French radon detector contributed by the ESA. Known as the Detection of Outgassing Radon (DORN), this payload will study how lunar dust and other volatiles (especially water) are transferred between the lunar regolith and the lunar exosphere. Then there’s the Italian INstrument for landing-Roving laser Retroreflector Investigations (INRRI), similar to those used by the Schiaparelli EDM module and InSight lander, that precisely measures distances from the lander to orbit.

The Chang’e-6 spacecraft stack shows a lunar rover attached to the mission lander. Credit: CAST

There’s also the Swedish Negative Ions on Lunar Surface (NILS), an instrument that will detect and measure negative ions reflected by the lunar surface. Lastly, there’s the Pakistani ICUBE-Q CubeSat developed by the Institute of Space Technology (IST) and Shanghai Jiao Tong University (SJTU), which will take images of the lunar surface using two optical cameras and measure the Moon’s magnetic field. The data these instruments provide will reveal new information about the lunar environment that will inform plans for long-duration missions on the surface.

By 2026, the Chang’e-6 mission will be joined by Chang’e-7, including an orbiter, lander, rover, and a mini-hopping probe. The data provided by the program will assist China’s plans to land taikonauts around the lunar south pole by 2030, followed by the completion of the ILRS by 2035.

Further Reading: CGTN

The post China is Going Back to the Moon Again With Chang'e-6 appeared first on Universe Today.

Earth is the only life-supporting planet we know of, so it’s tempting to use it as a standard in the search for life elsewhere. But the modern Earth can’t serve as a basis for evaluating exoplanets and their potential to support life. Earth’s atmosphere has changed radically over its 4.5 billion years.

A better way is to determine what biomarkers were present in Earth’s atmosphere at different stages in its evolution and judge other planets on that basis.

That’s what a group of researchers from the UK and the USA did. Their research is titled “The early Earth as an analogue for exoplanetary biogeochemistry,” and it appears in Reviews in Mineralogy. The lead author is Eva E. Stüeken, a PhD student at the School of Earth & Environmental Sciences, University of St Andrews, UK.

When Earth formed about 4.5 billion years ago, its atmosphere was nothing like it is today. At that time, the atmosphere and oceans were anoxic. About 2.4 billion years ago, free oxygen began to accumulate in the atmosphere during the Great Oxygenation Event, one of the defining periods in Earth’s history. But the oxygen came from life itself, meaning life was present when the Earth’s atmosphere was much different.

This isn’t the only example of how Earth’s atmosphere has changed over geological time. But it’s an instructive one and shows why searching for life means more than just searching for an atmosphere like modern Earth’s. If that’s the way we conducted the search, we’d miss worlds where photosynthesis hadn’t yet appeared.

In their research, the authors point out how Earth hosted a rich and evolving population of microbes under different atmospheric conditions for billions of years.

“For most of this time, Earth has been inhabited by a purely microbial biosphere albeit with seemingly increasing complexity over time,” the authors write. “A rich record of this geobiological evolution over most of Earth’s history thus provides insights into the remote detectability of microbial life under a variety of planetary conditions.”

It’s not just life that’s changed over time. Plate tectonics have changed and may have been ‘stagnant lid’ tectonics for a long time. In stagnant lid tectonics, plates don’t move horizontally. That can have consequences for atmospheric chemistry.

The main point is that Earth’s atmosphere does not reflect the solar nebula the planet formed in. Multiple intertwined processes have changed the atmosphere over time. The search for life involves not only a better understanding of these processes, but how to identify what stage exoplanets might be in.

This figure from the research shows how the abundance of major gases in Earth’s atmosphere has changed over time due to various factors. Image Credit: Stüeken et al. 2024.

It’s axiomatic that biological processes can have a dramatic effect on planetary atmospheres. “On the modern Earth, the atmospheric composition is very strongly controlled by life,” the researchers write. “However, any potential atmospheric biosignature must be disentangled from a backdrop of abiotic (geological and astrophysical) processes that also contribute to planetary atmospheres and would be dominating on lifeless worlds and on planets with a very small biosphere.”

The authors outline what they say are the most important lessons that the early Earth can teach us about the search for life.

The first is that the Earth has actually had three different atmospheres throughout its long history. The first one came from the solar nebula and was lost soon after the planet formed. That’s the primary atmosphere. The second one formed from outgassing from the planet’s interior. The third one, Earth’s modern atmosphere, is complex. It’s a balancing act involving life, plate tectonics, volcanism, and even atmospheric escape. A better understanding of how Earth’s atmosphere has changed over time gives researchers a better understanding of what they see in exoplanet atmospheres.

Earth’s Hadean Eon is a bit of a mystery to us because geologic evidence from that time is scarce. During the Hadean, Earth had its primary atmosphere from the solar nebula. But it soon lost it and accumulated another one via outgassing as the planet cooled. Credit: NASA

The second is that the further we look back in time, the more the rock record of Earth’s early life is altered or destroyed. Our best evidence suggests life was present by 3.5 billion years ago, maybe even by 3.7 billion years ago. If that’s the case, the first life may have existed on a world covered in oceans, with no continental land masses and only volcanic islands. If there had been abundant volcanic and geological activity between 3.5 and 3.7 billion years ago, there would’ve been large fluxes of CO2 and H2. Since these are substrates for methanogenesis, then methane may have been abundant in the atmosphere and detectable.

The third lesson the authors outline is that a planet can host oxygen-producing life for a long time before oxygen can be detected in an atmosphere. Scientists think that oxygenic photosynthesis appeared on Earth in the mid-Archean eon. The Archean spanned from 4 billion to 2.5 billion years ago, so mid-Archean is sometime around 3.25 billion years ago. But oxygen couldn’t accumulate in the atmosphere until the Great Oxygenation Event about 2.4 billion years ago. Oxygen is a powerful biomarker, and if we find it in an exoplanet’s atmosphere, it would be cause for excitement. But life on Earth was around for a long time before atmospheric oxygen would’ve been detectable.

Earth’s history is written in chemical reactions. This figure from the research shows the percentage of sulphur isotope fractionation in sediments. The sulphur signature disappeared after the GOE because the oxygen in the atmosphere formed an ozone shield. That blocked UV radiation, which stopped sulphur dioxide photolysis. “Anoxic planets where O2 production never occurs are more likely to resemble the early Earth prior to the GOE,” the authors explain. Image Credit: Stüeken et al. 2024.

The fourth lesson involves the appearance of horizontal plate tectonics and its effect on chemistry. “From the GOE onwards, the Earth looked tectonically similar to today,” the authors write. The oceans were likely stratified into an anoxic layer and an oxygenated surface layer. However, hydrothermal activity constantly introduced ferrous iron into the oceans. That increased the sulphate levels in the seawater which reduced the methane in the atmosphere. Without that methane, Earth’s biosphere would’ve been much less detectable. Complicated, huh?

“Planet Earth has evolved over the past 4.5 billion years from an entirely anoxic planet
with possibly a different tectonic regime to the oxygenated world with horizontal plate
tectonics that we know today,” the authors explain. All that complex evolution allowed life to appear and to thrive, but it also makes detecting earlier biospheres on exoplanets more complicated.

We’re at a huge disadvantage in the search for life on exoplanets. We can literally dig into Earth’s ancient rock to try to untangle the long history of life on Earth and how the atmosphere evolved over billions of years. When it comes to exoplanets, all we have is telescopes. Increasingly powerful telescopes, but telescopes nonetheless. While we are beginning to explore our own Solar System, especially Mars and the tantalizing ocean moons orbiting the gas giants, other solar systems are beyond our physical reach.

“We must instead remotely recognize the presence of alien biospheres and characterize their biogeochemical cycles in planetary spectra obtained with large ground- and space-based telescopes,” the authors write. “These telescopes can probe atmospheric composition by detecting absorption features associated with specific gases.” Probing atmospheric gases is our most powerful approach right now, as the JWST shows.

The JWST has made headlines for examining exoplanet atmospheres and identifying chemicals. A transmission spectrum of the hot gas giant exoplanet WASP-39 b, captured by Webb’s Near-Infrared Spectrograph (NIRSpec) on July 10, 2022, revealed the first definitive evidence for carbon dioxide in the atmosphere of a planet outside the Solar System. Credit: NASA, ESA, CSA, and L. Hustak (STScI). Science: The JWST Transiting Exoplanet Community Early Release Science Team

But as scientists get better tools, they’ll start to go beyond atmospheric chemistry. “We might also be able to recognize global-scale surface features, including light interaction with photosynthetic pigments and ‘glint’ arising from specular reflection of light by a liquid ocean.”

Understanding what we’re seeing in exoplanet atmospheres parallels our understanding of Earth’s long history. Earth could be the key to our broadening and accelerating search for life.

“Unravelling the details of Earth’s complex biogeochemical history and its relationship with remotely observable spectral signals is an important consideration for instrument design and our own search for life in the Universe,” the authors write.

The post What Can Early Earth Teach Us About the Search for Life? appeared first on Universe Today.

SpaceX revealed its new spacesuit designed for Crew Dragon passengers to unbuckle and float outside the spacecraft.

Starliner’s first crewed launch will mark just the sixth time ever that NASA astronauts have flown in a brand-new spacecraft

SpaceX launched another batch of its Starlink internet satellites today (May 6), the company's 46th orbital mission of the year already.

Two astronauts will have to wait to set off for the International Space Station aboard Boeing’s Starliner capsule, following a problem with the Atlas V rocket that caused the mission to be aborted before launch

Two astronauts will have to wait to set off for the International Space Station aboard Boeing’s Starliner capsule, following a problem with the Atlas V rocket that caused the mission to be aborted before launch

Two astronauts are about to set off for the International Space Station aboard Boeing’s Starliner capsule. If all goes well, Starliner will join SpaceX’s Dragon as a US shuttle into orbit

Two astronauts are about to set off for the International Space Station aboard Boeing’s Starliner capsule. If all goes well, Starliner will join SpaceX’s Dragon as a US shuttle into orbit

The eyebrows of the African wild dog have scientists wondering whether other canine species besides domestic dogs can make the irresistible “puppy-dog eyes” expression