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As it’s name suggests, dark matter is dark! That means it’s largely invisible to us and only detectable through its interaction with gravity. One of the leading theories to explain the stuff that makes up the majority of the matter in the Universe are WIMPs, Weakly Interacting Massive Particles. They are just theories though and none have been detected. An exciting new experiment called LUX-ZEPLIN has just completed 280 days of collecting data but still, no WIMPs have been detected above 9 Gev/c2. There are plans though to narrow the search.

The concept of dark matter was first proposed by Fritz Zwicky in 1930’s who noticed that galaxies were moving too fast to be held together by ‘normal’ visible matter. His work was expanded upon by Vera Rubin in the 1970’s who confirmed that stars around the outer regions of galaxies were moving faster than expected. The conclusion of these observations is that there was some form of invisible matter making up about 85% of the mass of the Universe. New results from LUX-ZEPLIN are homing in on the WIMP model to describe the nature of dark matter. 

Fritz Zwicky. Image Source: Fritz Zwicky Stiftung website

LUX-ZEPLIN is an instrument designed to detect dark matter. Located 1.6km underground at the Sanford Underground Research Facility in South Dakota, it’s a massive tank filled with 10 tons of liquid xenon waiting and watching for tiny interactions between dark matter and normal particles. It is shielded from cosmic radiation and other background noise by an onion layer design with each layer blocking out radiation or tracking particle interactions to rule out erroneous dark matter interactions. The principle is simple, a passing WIMP could knock into a xenon nucleus causing it to move and emit light and electrons in the process. It is these signals the teams are looking for. Along with new analytical techniques the teams using it hope they will finally unlock the mysteries of dark matter. 

A view of the Large Underground Xenon (LUX) dark matter detector. Shown are photomultiplier tubes that can ferret out single photons of light. Signals from these photons told physicists that they had not yet found Weakly Interacting Massive Particles (WIMPs) Credit: Matthew Kapust / South Dakota Science and Technology Authority

Following 280 days worth of data, no dark matter WIMPs were detected. Focussing their attention on WIMPs with a mass above 9 Gev/c2 the team found nothing despite the sensitivity of the detector. Having explored 9 Gev/c2 the team plans to start probing different energy levels as the hunt continues. The results had been announced at two physics conferences on 26 August TeV Particle Astrophysics 2024 in Chicago and LIDINE 2024 in São Paulo. 

The team applied an interesting new technique called ‘salting’ which adds fake WIMP signals during the collection of the data. The approach hides real data until the very end when an ‘unsalting’ technique removes them. This avoids unconscious bias and stops researchers from overly interpreting the data. 

Over the few years and by 2028, the team plan to collect at least 1,000 days of data which will be analysed using the new techniques. They will be using the data to study other rare phenomenon like the decay of xenon atoms, neutrino-less double beta decay and born-8 neutrinos from the Sun. There is still much work to do but the 250 scientists at LUX-ZEPLIN are hopeful. LUX-ZEPLIN’s physics coordinator Scott Kravitz from the University of Texas summed it up beautifully ‘Our ability to search for dark matter is improving at a rate faster than Moore’s Law. If you look at an exponential curve, everything before now is nothing. Just wait until you see what comes next.’

Source : Experiment sets new record in search for dark matter

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When the James Webb Space Telescope provided astronomers with a glimpse of the earliest galaxies in the Universe, there was some understandable confusion. Given that these galaxies existed during “Cosmic Dawn,” less than one billion years after the Big Bang, they seemed “impossibly large” for their age. According to the most widely accepted cosmological model—the Lambda Cold Dark Matter (LCDM) model—the first galaxies in the Universe did not have enough time to become so massive and should have been more modestly sized.

This presented astronomers with another “crisis in cosmology,” suggesting that the predominant model about the origins and evolution of the Universe was wrong. However, according to a new study by an international team of astronomers, these galaxies are not so “impossibly large” after all, and what we saw may have been the result of an optical illusion. In short, the presence of black holes in some of these early galaxies made them appear much brighter and larger than they actually were. This is good news for astronomers and cosmologists who like the LCDM the way it is!

The study was led by Katherine Chworowsky, a graduate student at the University of Texas at Austin (UT) and a National Science Foundation (NSF) Fellow. She was joined by colleagues from UT’s Cosmic Frontier Center, NSF’s NOIRLab, the Dunlap Institute for Astronomy & Astrophysics, the Mitchell Institute for Fundamental Physics and Astronomy, the Cosmic Dawn Center (DAWN), the Niels Bohr Institute, the Netherlands Institute for Space Research (SRON), NASA’s Goddard Space Flight Center, the European Space Agency (ESA), the Space Telescope Science Institute (STScI), and other prestigious universities and institutes. The paper that details their findings recently appeared in The Astrophysical Journal.

The first image taken by the James Webb Space Telescope, featuring the galaxy cluster SMACS 0723. Credit: NASA, ESA, CSA, and STScI

The data was acquired as part of the Cosmic Evolution Early Release Science (CEERS) Survey, led by Steven Finkelstein, a professor of astronomy at UT and a study co-author. In a previous study, Avishai Dekel and his colleagues at the Racah Institute of Physics at the Hebrew University of Jerusalem (HUJI) argued that the prevalence of low-density dust clouds in the early Universe allowed for rapid star formation in galaxies. Dekel and Zhaozhou Li (a Marie Sklodowska-Curie Fellow at HUJI) were also co-authors of this latest study.

As Chworowsky and her colleagues explained, the observed galaxies only appeared massive because their central black holes were rapidly consuming gas. This process causes friction, causing the gas to emit heat and light, creating the illusion of there being many more stars and throwing off official mass estimates. These galaxies appeared as “little red dots” in the Webb image (shown below). When removed from the analysis, the remaining galaxies were consistgent with what the standard LCDM model predicts.

“So, the bottom line is there is no crisis in terms of the standard model of cosmology,” Finkelstein said in a UT News release. “Any time you have a theory that has stood the test of time for so long, you have to have overwhelming evidence to really throw it out. And that’s simply not the case.”

However, there is still the matter of the number of galaxies in the Webb data, which are twice as many as the standard model predicts. A possible explanation is that stars formed more rapidly in the early Universe. Essentially, stars are formed from clouds of dust and gas (nebulae) that cool and condense to the point where they undergo gravitational collapse, triggering nuclear fusion. As the star’s interior heats up, it generates outward pressure that counteracts gravity, preventing further collapse. The balance of these opposing forces makes star formation relatively slow in our region of the cosmos.

The galaxy cluster SMACS0723, with the five galaxies selected for closer study. Credit: NASA, ESA, CSA, STScI / Giménez-Arteaga et al. (2023), Peter Laursen (Cosmic Dawn Center).

According to some theories, the Universe was much denser than it is today, which prevented stars from blowing out gas during formation, thus making the process more rapid. These findings echo what Dekel and his colleagues argued in their previous paper, though it would account for there being more galaxies rather than several massive ones. Similarly, the CEERS team and other research groups have obtained spectra from these black holes that indicate the presence of fast-moving hydrogen gas, which could mean that they have accretion disks.

The swirling of these disks could provide some of the luminosity previously mistaken for stars. In any case, further observations of these “little red dots” are pending, which should help resolve any remaining questions about how massive these galaxies are and whether or not star formation was more rapid during the early Universe. So, while this study has shown that the LCDM model of cosmology is safe for now, its findings raise new questions about the formation process of stars and galaxies in the early Universe.

“And so, there is still that sense of intrigue,” said Chworowsky. “Not everything is fully understood. That’s what makes doing this kind of science fun, because it’d be a terribly boring field if one paper figured everything out, or there were no more questions to answer.”

Further Reading: UT News, The Astronomical Journal

The post Remember those Impossible Galaxies Found by JWST? It Turns Out They Were Possible After All appeared first on Universe Today.

The merging of black holes and neutron stars are among the most energetic events in the universe. Not only do they emit colossal amounts of energy, they can also be detected through gravitational waves. Observatories like LIGO/Virgo (Laser Interferometer Gravitational Wave Observatory) and KAGRA (The Kamioka Gravitational Wave Detector) have detected their gravitational waves but new gravitational wave observatories are now thought to be able to detect the collapse of a massive rapidly spinning star before it becomes a black hole. According to new research, collapsing stars within 50 million light years should be detectable. 

The acceleration of massive objects can create ripples in space-time known as gravitational waves. They were first predicted by Albert Einstein in 1915 in his General Theory of Relativity. The waves are thought to travel at the speed of light and carry energy across the cosmos. Unlike electromagnetic waves, the gravitational waves seem to interact weakly with matter which allows them to pass unimpeded through stars, planets and galaxies. In 2015, the first gravitational waves were detected by the LIGO.

LIGO Observatory

Black holes and neutron stars are the remains of the death of stars. When supermassive stars reach the end of their lives they create astronomically (pardon the pun) dense objects. Neutron stars are stellar cores where the space between neutrons has been squeezed out leaving behind one great big neutron, often just a few tens of kilometres across. The remains of even more massive stars get compressed to an object of infinitely small size, a singularity, the power house of a black hole. 

In a paper published in The Astrophysical Journal Letters by Ore Gottlieb and team, it proposes how the collapse and death of massive stars (of the region 15 to 20 times the mass of the Sun) can generate gravitational waves. As the star ends its life, the core runs out of fuel and no longer generates the thermonuclear force to stop the collapse. The collapse leaves behind a large disk that quickly spirals around before falling into the black hole and it is this that it is thought, generates gravitational waves. The team goes on to suggest that the various gravity wave detectors on Earth may well be able to detect them.

An artist’s illustration of a supermassive black hole (SMBH.) The SMBH in a distant galaxy expelled all the material in its accretion disk, clearing out a vast area. Image Credit: ESA

To date, only merger events have been observed through gravitational waves. The simulations from the study took into account stellar evolution models including magnetic fields and cooling rates in the moments after core collapse. The simulations showed that the collapse events produce gravitational waves powerful enough to be detected from a distance of 50 million light years. The more powerful events already detected are ten times more powerful. 

The results are a surprise to the team that expected the results to show a jumble of waves that would be difficult to discern above the background noise of the universe. They even suggest that it’s possible that existing data may already hold observations of such events. 

To fully model the collapse events and how the gravity wave data may present itself, an estimated 1 million collapse simulations need to be run. Alas this is an expensive undertaking and unlikely to secure funding. Instead gravity wave astronomers are searching through existing data, looking for signals that are similar to the simulations the team have already run. One approach is to search for supernova events and to see if gravity wave observations detected any signals at the same time. The task however, is a daunting one but the hunt continues. 

Source : New Detectable Gravitational Wave Source From Collapsing Stars Predicted From Simulations

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The search for extraterrestrial intelligence (SETI) has fascinated us for decades. Now a team of researchers have used the Murchison Widefield Array in Australia to scan great swathes of sky for alien signals. Unusually for a SETI project, this one focussed attention on 2,800 galaxies instead of stars within our own. They have been on the lookout for advanced civilisations that are broadcasting their existence using the power of an entire star. Alas they weren’t successful but its an exciting new way to search for alien intelligence. 

Our first attempts to search for alien intelligence began back in 1960 with Project Ozma. It was led by astronomer Frank Drake and used the 85 foot radio telescope at Green Bank in West Virginia. The aim was to try and detect alien radio signals from Epsilon Eridani and Tau Ceti, should they have existed. Alas they found nothing but it marked the first step in a scientific approach to search for extraterrestrial intelligence. Typically SETI tends to focus on electromagnetic signals such as radio waves an in particular unusual patterns that could suggest intentional communication. 

Radio telescopes monitor the sky at the Allen Telescope Array in California. Finding a signal from a distant civilization is one way we could experience first contact with ET. (SETI Institute Photo)

This recent attempt to try out a new approach was led by Dr Chenoa Tremblay of the SETI Institute and Prof. Steven Tingay from the Curtin University. The approach was to utilise the magnificent field of view of the Murchison Widefield Array (MWA) which allows one observation to cover 2,800 galaxies. Among them, there are 1,300 galaxies that we know the distance too. The MWA in Western Australia utilises low frequencies (100MHz) to probe the distant galaxies. 

By searching these galaxies for signs of alien signals we are actually looking for advanced civilisations. It’s one thing to be able to send radio signals across interstellar space, indeed we have been doing that for decades since the advent of radio communication. As radio signals propagate across space, they weaken and certainly could not traverse the immense distances between the galaxies. It’s just possible that advanced civilisations might have the technology to harness the power of their Sun and perhaps other stars in their galaxy to send signals powerful enough to travel the millions of light years between galaxies. 

I quite love the idea of advanced civilisations that may have developed the technology to transmit ‘technosignatures’ or signs of alien technology across the Universe but alas the study did not find any. Queue sad emoji

Solar sails are an exciting way to travel through the Solar System because they get their propulsion from the Sun. NASA has developed several solar sails, and their newest, the Advanced Composite Solar Sail System (or ACS3), launched a few months ago into low-Earth orbit. After testing, NASA reported today that they extended the booms, deploying its 80-square-meter (860 square feet) solar sail. They’ll now use the sail to raise and lower the spacecraft’s orbit, learning more about solar sailing.

“The Sun will continue burning for billions of years, so we have a limitless source of propulsion. Instead of launching massive fuel tanks for future missions, we can launch larger sails that use ‘fuel’ already available,” said Alan Rhodes, the mission’s lead systems engineer at NASA’s Ames Research Center, earlier this year. “We will demonstrate a system that uses this abundant resource to take those next giant steps in exploration and science.”

And for all you skywatchers out there, NASA said that given the reflectivity of the large sail and its position in orbit (about 1,000 km/600 miles) above Earth, ACS3 should be easily visible at times in the night sky. The Heavens Above website already has ACS3 listed on their page (just put in your location to see when to catch the solar sail passing over your area.) There should be info and updates available on social media, so follow NASA.gov and @NASAAmes on X and Instagram for updates.

ACS3 is part of NASA’s Small Spacecraft Technology program, which has the objective of deploying small missions that demonstrate unique capabilities rapidly. ACS3 launched in April 2024 aboard Rocket Lab’s Electron rocket from New Zealand. The spacecraft is a twelve-unit (12U) CubeSat built by NanoAvionics that’s about the size of a microwave oven. The biggest challenge designing and creating lightweight booms that could be small enough to fit inside the spacecraft while being able to extend to about 9 meters (30 ft) per side, and being strong enough to support the solar sail. The lightweight but strong composite carbon fiber boom system unrolled from the spacecraft to form rigid tubes that support the ultra-thin, reflective polymer sail.

This video shows how the booms work and the sail deploys:

When fully deployed, the sail forms a square that is about half the size of a tennis court. To change direction, the spacecraft angles its sails. Now with the boom deployment, the ACS3 team will perform maneuvers with the spacecraft, angling the sails and to change the spacecraft’s orbit.

The primary goal of the mission was to demonstrate boom deployment. With that now successfully achieved, the ACS3 team also hopes the mission will prove that their solar sail spacecraft can actually work for future solar sail-equipped science and exploration missions.?

This image shows the ACS3 being unfurled at NASA’s Langley Research Center. The solar wind is reliable but not very powerful. It requires a large sail area to power a spacecraft effectively. The ACS2 is about 9 meters (30 ft) per side, requiring a strong, lightweight boom system. Image Credit: NASA

Since ACS3 is a demonstration mission, the goal is to build larger sails that can generate more thrust. With these unique composite carbon fiber booms, the ACS3 system has the potential to support sails as large as 2,000 square meters, or about 21,500 square feet, or about half the area of a soccer field.

“The hope is that the new technologies verified on this spacecraft will inspire others to use them in ways we haven’t even considered,” Rhodes said.

And look for photos of the ACS3 fully deployed sail next week. The spacecraft has four cameras which captured a panoramic view of the reflective sail and supporting composite booms. NASA said that high-resolution imagery from these cameras will be available on Wednesday, Sept. 4.

NASA is providing updates on this mission on their Small Satellite Missions blog page.

The post NASA's New Solar Sail Extends Its Booms and Sets Sail appeared first on Universe Today.

Rogue Planets, or free-floating planetary-mass objects (FFPMOs), are planet-sized objects that either formed in interstellar space or were part of a planetary system before gravitational perturbations kicked them out. Since they were first observed in 2000, astronomers have detected hundreds of candidates that are untethered to any particular star and float through the interstellar medium (ISM) of our galaxy. In fact, some scientists estimate that there could be as many as 2 trillion rogue planets (or more!) wandering through the Milky Way alone.

In recent news, a team of astronomers working with the James Webb Space Telescope (JWST) announced the discovery of six rogue planet candidates in an unlikely spot. The planets, which include the lightest rogue planet ever identified (with a debris disk around it), were spotted during Webb‘s deepest survey of the young nebula NGC 1333, a star-forming cluster about a thousand light-years away in the Perseus constellation. These planets could teach astronomers a great deal about the formation process of stars and planets.

The team was led by Adam Langeveld, an Assistant Research Scientist in the Department of Physics and Astronomy at Johns Hopkins University (JHU). He was joined by colleagues from the Carl Sagan Institute, the Instituto de Astrofísica e Ciências do Espaço, the Trottier Institute for Research on Exoplanets, the Mont Mégantic Observatory, the Herzberg Astronomy and Astrophysics Research Centre, the University of Texas at Austin, the University of Victoria, the Scottish Universities Physics Alliance (SUPA) at the University of St Andrews. The paper detailing the survey’s findings has been accepted for publication in The Astronomical Journal.

Most of the rogue planets detected to date were discovered using Gravitational Microlensing, while others were detected via Direct Imaging. The former method relies on “lensing events,” where the gravitational force of massive objects alters the curvature of spacetime around them and amplifies light from more distant objects. The latter consists of spotting brown dwarfs (objects that straddle the line between planets and stars) and massive planets directly by detecting the infrared radiation produced within their atmospheres.

In their paper, the team describes how the discovery occurred during an extremely deep spectroscopic survey of NGC1333. Using data from Webb‘s Near-Infrared Imager and Slitless Spectrograph (NIRISS), the team measured the spectrum of every object in the observed portion of the star cluster. This allowed them to reanalyze spectra from 19 previously observed brown dwarfs and led to the discovery of a new brown dwarf with a planetary-mass companion. This latter observation was a rare find that already challenges theories of how binary systems form. But the real kicker was the detection of six planets with 5-10 times the mass of Jupiter (aka. super-Jupiters).

This means these six candidates are among the lowest-mass rogue planets ever found that formed through the same process as brown dwarfs and stars. This was the purpose of the Deep Spectroscopic Survey for Young Brown Dwarfs and Free-Floating Planets survey, which was to investigate massive objects that are not quite large enough to become stars. The fact that Webb’s observations revealed no objects lower than five Jupiter masses (which it is sensitive enough to detect) is a strong indication that stellar objects lighter than are more likely to form the way planets do.

Said lead author Langeveld in a statement released by JHU’s new source (the Hub):

“We are probing the very limits of the star-forming process. If you have an object that looks like a young Jupiter, is it possible that it could have become a star under the right conditions? This is important context for understanding both star and planet formation.”

New wide-field view mosaic from the James Webb Space Telescope spectroscopic survey of NGC1333 with three of the newly discovered free-floating planetary-mass objects indicated by green markers. Credit: ESA/Webb, NASA & CSA, A. Scholz, K. Muzic, A. Langeveld, R. Jayawardhana

The most intriguing of the rogue planets was also the lightest: an estimated five Jupiter masses (about 1,600 Earths). Since dust and gas generally fall into a disk during the early stages of star formation, the presence of this debris ring around the one planet strongly suggests that it formed in the same way stars do. However, planetary systems also form from debris disks (aka. circumsolar disks), which suggests that these objects may be able to form their own satellites. This suggests that these massive planets could be a nursery for a miniature planet system – like our Solar System, but on a much smaller scale.

Said Johns Hopkins Provost Ray Jayawardhana, an astrophysicist and senior author of the study (who also leads the survey group):

“It turns out the smallest free-floating objects that form like stars overlap in mass with giant exoplanets circling nearby stars. It’s likely that such a pair formed the way binary star systems do, from a cloud fragmenting as it contracted. The diversity of systems that nature has produced is remarkable and pushes us to refine our models of star and planet formation…

“Our observations confirm that nature produces planetary mass objects in at least two different ways—from the contraction of a cloud of gas and dust, the way stars form, and in disks of gas and dust around young stars, as Jupiter in our own solar system did.”

In the coming months, the team plans to use Webb to conduct follow-up studies of these rogue planets’ atmospheres and compare them to those of brown dwarfs and gas giants. They also plan to search the star-forming region for other objects with debris disks to investigate the possibility of mini-planetary systems. The data they obtain will also help astronomers refine their estimates on the number of rogue planets in our galaxy. The new Webb observations indicate that such bodies account for about 10% of celestial bodies in the targeted cluster.

Current estimates place the number of stars in our galaxy between 100 and 400 billion stars and the number of planets between 800 billion and 3.2 trillion. At 10%, that would suggest that there are anywhere from 90 to 360 billion rogue worlds floating out there. As we have explored in previous articles, we might be able to explore some of them someday, and our Sun may even capture a few!

Further Reading: HUB

The post Webb Discovers Six New “Rogue Worlds” that Provide Clues to Star Formation appeared first on Universe Today.

Scientists have discovered that Earth has a third field. We all know about the Earth’s magnetic field. And we all know about Earth’s gravity field, though we usually just call it gravity.

Now, a team of international scientists have found Earth’s global electric field.

It’s called the ambipolar electric field, and it’s a weak electric field that surrounds the planet. It’s responsible for the polar wind, which was first detected decades ago. The polar wind is an outflow of plasma from the polar regions of Earth’s magnetosphere. Scientists hypothesized the ambipolar field’s existence decades ago, and now they finally have proof.

The discovery is in a new article in Nature titled “Earth’s ambipolar electrostatic field and its role in ion escape to space.” The lead author is Glyn Collinson from the Heliophysics Science Division at NASA Goddard Space Flight Center.

“It’s like this conveyor belt, lifting the atmosphere up into space.”

Glyn Collinson, Heliophysics Science Division, NASA Goddard Space Flight Center

The Space Age gained momentum back in the 1960s as the USA and USSR launched more and more satellites. When spacecraft passed over the Earth’s poles, they detected an outflow of particles from Earth’s atmosphere into space. Scientists named this the polar wind, but for decades, it was mysterious.

Scientists expect some particles from Earth to “leak” into space. Sunlight can cause this. But if that’s the case, the particles should be heated. The wind is mysterious because many particles in it are cold despite moving at supersonic speeds.

“Something had to be drawing these particles out of the atmosphere,” said lead author Collinson.

Collinson is also the Principal Investigator for NASA’s “Endurance” Sounding Rocket Mission. “The purpose of the Endurance mission was to make the first measurement of the magnitude and structure of the electric field generated by Earth’s ionosphere,” NASA writes in their mission description. Endurance launched on May 22nd, 2022, from Norway’s Svalbard Archipelago.

This image shows NASA’s Endurance rocket launching from Ny-Ålesund, Svalbard, Norway. It flew for 19 minutes to an altitude of about 780 km (484 mi) above Earth’s sunlit polar cap. It carried six science instruments and could only be launched in certain conditions to be successful. Image Credit: NASA/Brian Bonsteel.

“Svalbard is the only rocket range in the world where you can fly through the polar wind and make the measurements we needed,” said Suzie Imber, a space physicist at the University of Leicester, UK, and co-author of the paper.

Svalbard is key because there are open magnetic field lines above Earth’s polar caps. These field lines provide a pathway for ions to outflow to the magnetosphere.

This figure from the research shows Endurance’s flight profile and its path over Earth. The rocket had to fly near the open magnetic field lines that exist at Svalbard’s high polar latitudes. Image Credit: Collinson et al. 2024.

After it was launched, Collinson said, “We got fabulous data all through the flight, though it will be a while before we can really dig into it to see if we achieved our science objective or not.”

Now, the data is in, and the results show that Earth has a global electric field.

Prior to its discovery, scientists hypothesized that the field was weak and that its effects could only be felt over hundreds of kilometres. Even though it was first proposed 60 years ago, scientists had to wait for technology to advance before they could measure it. In 2016, Collinson and his colleagues began inventing a new instrument that could measure the elusive field.

At about 250 km (150 mi) above the Earth’s surface, atoms break apart into negatively charged electrons and positively charged ions. Electrons are far lighter than ions, and the tiniest energetic jolt can send them into space. Ions are more than 1800 times heavier, and gravity draws them back to the surface.

If gravity were the only force at work, the two populations would separate over time and simply drift apart. But that’s not what happens.

Electrons and ions have opposite electrical charges. They’re attracted to one another and an electric field forms that keeps them together. This counteracts some of gravity’s power.

The field is called ambipolar because it’s bidirectional. That means it works in both directions. As ions sink down due to gravity, the electrical charges mean that the ions drag some of the electrons down with them. However, at the same time, electrons lift ions high into the atmosphere with them as they attempt to leave the atmosphere and escape into space.

via GIPHY

The result of all this is that the ambipolar field extends the atmosphere’s height, meaning some of the ions escape with the polar wind.

After decades of hypothesizing and theorizing, the Endurance rocket measured a change in electric potential of only 0.55 volts. That’s extremely weak but enough to be measurable.

“A half a volt is almost nothing — it’s only about as strong as a watch battery,” Collinson said. “But that’s just the right amount to explain the polar wind.”

Hydrogen ions are the most plentiful particles in the polar wind. Endurance’s results show that these ions experience an outward force from the magnetic field that’s 10.6 times more powerful than gravity. “That’s more than enough to counter gravity — in fact, it’s enough to launch them upwards into space at supersonic speeds,” said Alex Glocer, Endurance project scientist at NASA Goddard and co-author of the paper.

Hydrogen ions are light, but even the heavier particles in the polar wind are lifted. Oxygen ions in the weak electrical field effectively weigh half as much, yet they’re boosted to greater heights, too. Overall, the ambipolar field makes the ionosphere denser at higher altitudes than it would be without the field’s lofting effect. “It’s like this conveyor belt, lifting the atmosphere up into space,” Collinson added.

“The measurements support the hypothesis that the ambipolar electric field is the primary driver of ionospheric H+ outflow and of the supersonic polar wind of light ions escaping from the polar caps,” the authors explain in their paper.

“We infer that this increases the supply of cold O+ ions to the magnetosphere by more than 3,800%,” the authors write. At that point, other mechanisms come into play. Wave-particle interactions can heat the ions, accelerating them to escape velocity.

These results raise other questions. How does this field affect Earth? Has the field affected the planet’s habitability? Do other planets have these fields?

Back in 2016, the European Space Agency’s Venus Express mission detected a 10-volt electric potential surrounding the planet. This means that positively charged particles would be pulled away from the planet’s surface. This could draw away oxygen.

Scientists think that Venus may have once had plentiful water. However, since sunlight splits water into hydrogen and oxygen, the electric field could’ve siphoned the oxygen away, eliminating the planet’s water. This is theoretical, but it begs the question of why the same thing hasn’t happened on Earth.

The ambipolar field is fundamental to Earth. Its role in the evolution of the planet’s atmosphere and biosphere is yet to be understood, but it must play a role.

“Any planet with an atmosphere should have an ambipolar field,” Collinson said. “Now that we’ve finally measured it, we can begin learning how it’s shaped our planet as well as others over time.”

The post A NASA Rocket Has Finally Found Earth’s Global Electric Field appeared first on Universe Today.

Astronomers at the International Astronomical Union report that we have now detected more than 200 gravitational-wave events, most the merger of two black holes.

The post Status Report: Gravitational Waves appeared first on Sky & Telescope.

The Perseids peak on Sunday night, August 11-12 and just might be joined by a colorful display of northern lights. 

The post Tonight's Perseid Meteor Shower May Be Dipped in Aurora Sauce appeared first on Sky & Telescope.

It's time again for the annual August meteor-shower fest, the Perseids. This year's display should be a beauty with only minor moonlight and a special surprise at dawn.

The post Woo-hoo — The Perseid Meteor Shower Is Coming! appeared first on Sky & Telescope.

The Perseid meteor shower peaks late Sunday night August 11th and maybe Monday night too. Jupiter and Mars have a close conjunction on the morning of the 14th, looking radically different in the same telescopic view.

The post This Week's Sky at a Glance, August 9 – 18 appeared first on Sky & Telescope.

The year’s long-awaited Perseid meteor shower will be accompanied by a graceful planetary conjunction. It’s well worth staying up all night to watch.

The post Prepare for the Perseids and a Pretty Planetary Pairing appeared first on Sky & Telescope.

Fifteen years ago, the Hubble Space Telescope gazed intently at the infrared glow of galaxies in a tiny fraction of the sky. New research shows how this patch of space has changed since then.

The post The Hubble Ultra-Deep Field, 15 Years Later appeared first on Sky & Telescope.

New data on the brightest pulsar observed with a telescope on the International Space Station suggests neutron star interiors are "squishy."

The post Neutron Stars Might Be Squishy Inside appeared first on Sky & Telescope.

Amateur astronomers are all life-long learners — and this "back to school" time of year provides just the right motivation.

The post Enroll in the School of Stars appeared first on Sky & Telescope.

The Perseid meteors ramp up this week to their peak. Saturn is nicely up in the east by late evening. Jupiter and Mars near their conjunction in the morning sky. And there's a story behind Poniatowski's Bull.

The post This Week's Sky at a Glance, August 2 – 11 appeared first on Sky & Telescope.

"Leopard spots" on a Mars rock could come from life — or they could simply be a sign of a type of chemical reaction that requires water.

The post Does This Mars Rock Show a "Potential Biosignature"? Or Just "Wet Chemistry"? appeared first on Sky & Telescope.

Let’s go on a night-sky tour of the stars and planets that you’ll see overhead during August. Find a good seat for some great “shooting stars,” watch Saturn climb in the eastern sky in early evening, check out the summer's brightest stars, and start looking for a once-in-your-lifetime star blast. 

The post August Podcast: Nova Watch in the Northern Crown appeared first on Sky & Telescope.

Future funding for NASA's remaining Great Observatories — Chandra X-ray Observatory and Hubble Space Telescope — is still up in the air.

The post Reading the Tea Leaves: The Future of the Hubble and Chandra Space Telescopes appeared first on Sky & Telescope.

A professional astronomer turned dark-sky champion, David L. Crawford became synonymous with the fight against light pollution around the world.

The post David Crawford, 1931–2024 appeared first on Sky & Telescope.