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The universe is undeniably vast, and from our perspective, it may seem like Earth is in the middle of everything. But is there a center of the cosmos, and if so, where is it? If the Big Bang started the universe, then where did it all come from, and where is it going?

Is the Lion Nebula the real ruler of the

What a wonderful arguably simple solution. Here’s the problem, we travel to Mars but how do we feed ourselves? Sure we can take a load of food with us but for the return trip that’s a lot. If we plan to colonise the red planet we need even more. We have to grow or somehow create food while we are there. The solution is an already wonderfully simple ‘biosphere’ style system; a fish tank! New research suggests fish could be raised in an aquatic system and nutrient rich water can fertilise and grow plants in the regolith! A recent simulation showed vegetables could be grown in regolith fertilised by the fish tank water!

In the next few decades we may well see human beings colonise Mars. The red planet is 54.6 million km away which, even on board a rocket, takes about 7 months to get there! Future colonists could simply have supply ships drop all they need but that becomes ridiculously expensive to sustain and frankly, isn’t sustainable. The lucky people that colonise Mars will just have to find some way to grow what they need. 

If you have watched ‘The Martian’ movie with Matt Damon you will know how unforgiving the Martian environment is. Ok the film was a little out on scientific accuracy in places but it certainly showed how inhospitable it really is there. Matt managed to cultivate a decent crop of potatoes in Martian regolith fertilised in human faeces.This may not be quite so practical in real life and there may be alternative, less smelly – and dangerous – alternatives. 

NASA astronaut, Dr. Mark Watney played by Matt Damon, as he’s stranded on the Red Planet in ‘The Martian’. (Credit: 20th Century Fox)

Taking the assumption that colonists will have to grow fresh produce locally, a team of researchers decided to explore how feasible this might be. On first glance, it may seem not too great an idea after all, the atmosphere is toxic with 95% carbon dioxide (compared to just 0.04% on Earth). There is a similar length of day on Mars but being able to grow crops will require longer periods of lighting. It is possible at least water may be collected from the ice which forms on and in the Martian rocks.  The rocks most certainly have water stored away but organic compounds that we know of. 

The team wanted to see how fish could help and whether the water from the system could be used to impart nutrients into the Martian regolith. To test the idea, they setup an aquaponic system with fish in tanks to generate the nutrient rich liquid.

The results were very promising. They found that aquaponic systems not only facilitate growing plants within the system itself but the nutrient rich water performed as an excellent fertiliser. This took the organically deficient regolith and turned it into something akin to useable soil. The fish used in the study were tilapia (Oreochromis niloticus) and using them, the team managed to grow potatoes, tomatoes, beans, carrots and much more. To enable all this to happen, the fish received sufficient light and other environmental stimulus. The plants were grown and indeed thrived in a tent that simulated Mars in every way possible. 

It’s an interesting aside that the study not only benefits future space travellers but those inhabitants of more environmentally hostile places on Earth. 

Source : Fish and chips on Mars: our research shows how colonists could produce their own food

The post Fish Could Turn Regolith into Fertile Soil on Mars appeared first on Universe Today.

One of the main scientific objectives of next-generation observatories (like the James Webb Space Telescope) has been to observe the first galaxies in the Universe – those that existed at Cosmic Dawn. This period is when the first stars, galaxies, and black holes in our Universe formed, roughly 50 million to 1 billion years after the Big Bang. By examining how these galaxies formed and evolved during the earliest cosmological periods, astronomers will have a complete picture of how the Universe has changed with time.

As addressed in previous articles, the results of Webb‘s most distant observations have turned up a few surprises. In addition to revealing that galaxies formed rapidly in the early Universe, astronomers also noticed these galaxies had particularly massive supermassive black holes (SMBH) at their centers. This was particularly confounding since, according to conventional models, these galaxies and black holes didn’t have enough time to form. In a recent study, a team led by Penn State astronomers has developed a model that could explain how SMBHs grew so quickly in the early Universe.

The research team was led by W. Niel Brandt, the Eberly Family Chair Professor of Astronomy and Astrophysics at Penn State’s Eberly College of Science. Their research is described in two papers presented at the 244th meeting of the American Astronomical Society (AAS224), which took place from June 9th to June 13th in Madison, Wisconsin. Their first paper, “Mapping the Growth of Supermassive Black Holes as a Function of Galaxy Stellar Mass and Redshift,” appeared on March 29th in The Astrophysical Journal, while the second is pending publication. Fan Zou, an Eberly College graduate student, was the lead author of both papers.

Illustration of an active quasar. New research shows that SMBHs eat rapidly enough to trigger them. Credit: ESO/M. Kornmesser

As they note in their papers, SMBHs grow through two main channels: by accreting cold gas from their host galaxy or merging with the SMBHs of other galaxies. When it comes to accretion, previous research has shown that a black hole’s accretion rate (BHAR) is strongly linked to its galaxy’s stellar mass and the redshift of its general stellar population. “Supermassive black holes in galaxy centers have millions-to-billions of times the mass of the Sun,” explained Zhou in a recent NASA press release. How do they become such monsters? This is a question that astronomers have been studying for decades, but it has been difficult to track all the ways black holes can grow reliably.”

For their research, the team relied on forefront X-ray sky survey data obtained by NASA’s Chandra X-ray Observatory, the ESA’s X-ray Multi-Mirror Mission-Newton (XMM-Newton), and the Max Planck Institute for Extraterrestrial Physics’ eROSITA telescope. They measured the accretion-driven growth in a sample of 8000 active galactic nuclei (AGNs) located in 1.3 million galaxies. This was combined with IllustrisTNG, a suite of state-of-the-art cosmological simulations that model galaxy formation, evolution, and mergers from Cosmic Dawn to the present. This combined approach has provided the best modeling to date of SMBH growth over the past 12 billion years. Said Brandt:

“During the process of consuming gas from their hosting galaxies, black holes radiate strong X-rays, and this is the key to tracking their growth by accretion. We measured the accretion-driven growth using X-ray sky survey data accumulated over more than 20 years from three of the most powerful X-ray facilities ever launched into space.

“In our hybrid approach, we combine the observed growth by accretion with the simulated growth through mergers to reproduce the growth history of supermassive black holes. With this new approach, we believe we have produced the most realistic picture of the growth of supermassive black holes up to the present day.”

This still image shows the timeline running from the Big Bang on the right towards the present on the left. In the middle is the Reionization Period where the initial bubbles caused the cosmic dawn. Credit: NASA SVS

Their results indicate that SMBHs of all masses grew much more rapidly when the Universe was younger and that accretion was the main driver of black hole growth in most cases. They also noted that mergers made notable secondary contributions, especially the largest SMBHs during the past 5 billion years. This suggests that new SMBHs kept emerging during the early Universe, but the formation process was all but settled by ca. 7 billion years ago. As Zou concluded:

“With our approach, we can track how central black holes in the local universe most likely grew over cosmic time. As an example, we considered the growth of the supermassive black hole in the center of our Milky Way Galaxy, which has a mass of 4 million solar masses. Our results indicate that our Galaxy’s black hole most likely grew relatively late in cosmic time.”

In addition to Zou and Brandt, the international team comprised researchers from the Institute for Gravitation and the Cosmos and the Departments of Physics, Statistics, and Astronomy and Astrophysics at Penn State. Other team members included researchers from the University of Michigan, the Nanjing University in China, the University of Science and Technology of China, the Max Planck Institute for Extraterrestrial Physics, and the University of Groningen in the Netherlands.

Further Reading: Chandra X-ray Observatory, The Astrophysical Journal

The post New Simulation Explains how Supermassive Black Holes Grew so Quickly appeared first on Universe Today.

Astronomers are using the Chandra X-ray Observatory to study stars' radiation and establish the feasibility of exoplanet habitability.

On Episode 115 of This Week In Space, Rod and Tariq talk with Alex Young of NASA's Goddard Space Flight Center about the sun and solar activity cycles.

Cosmic rays from distant stars and galaxies and solar energetic particles from the Sun bombard the moon's surface, and exposure to these particles can pose a risk to human health.

An examination of the iconic Griffith Observatory, which has appeared in scores of films throughout the history of Hollywood.

Breakdancing will hit the global stage at the 2024 Summer Olympic Games in Paris, and this physicist is excited to break down the science

Eventually, all galaxies, including our own Milky Way, will meet their end. But how do galaxies die? If you're in the mood to destroy an entire galaxy, you have several options, depending on your desired level of destructiveness.

4 Min Read Tropical Solstice Shadows June 20, 2024, marks the summer solstice — the beginning of astronomical summer — in the Northern Hemisphere. Credits: NASA/DSCOVR EPIC

Solstices mark the changing of seasons, occur twice a year, and feature the year’s shortest and longest daylight hours – depending on your hemisphere. These extremes in the length of day and night make solstice days more noticeable to many observers than the subtle equality of day and night experienced during equinoxes. Solstices were some of our earliest astronomical observations, celebrated throughout history via many summer and winter celebrations.

Solstices occur twice yearly, and in 2024 they arrive on June 20 at 4:50 PM EDT (20:50 UTC), and December 21 at 4:19 AM EST (9:18 UTC). The June solstice marks the moment when the Sun is at its northernmost position in relation to Earth’s equator, and the December solstice marks its southernmost position. The summer solstice occurs on the day when the Sun reaches its highest point at solar noon for regions outside of the tropics, and those observers experience the longest amount of daylight for the year. Conversely, during the winter solstice, the Sun is at its lowest point at solar noon for the year and observers outside of the tropics experience the least amount of daylight- and the longest night – of the year.

The June solstice marks the beginning of summer for folks in the Northern Hemisphere and winter for Southern Hemisphere folks, and in December the opposite is true, as a result of the tilt of Earth’s axis of rotation. For example, this means that the Northern Hemisphere receives more direct light from the Sun than the Southern Hemisphere during the June solstice. Earth’s tilt is enough that northern polar regions experience 24-hour sunlight during the June solstice, while southern polar regions experience 24-hour night, deep in Earth’s shadow. That same tilt means that the Earth’s polar regions also experience a reversal of light and shadow half a year later in December, with 24 hours of night in the north and 24 hours of daylight in the south. Depending on how close you are to the poles, these extreme lighting conditions can last for many months, their duration deepening the closer you are to the poles.

A presenter from the San Antonio Astronomy Club in Puerto Rico demonstrating some Earth-Sun geometry to a group during a “Zero Shadow Day” event.  As Puerto Rico lies a few degrees south of the Tropic of Cancer, their two zero shadow days arrive just a few weeks before and after the June solstice. Globes are a handy and practical way to help visualize solstices and equinoxes for large outdoor groups, especially outdoors during sunny days!Credit: Juan Velázquez / San Antonio Astronomy Club

While solstice days are very noticeable to observers in mid to high latitudes, that’s not the case for observers in the tropics – areas of Earth found between the Tropic of Cancer and the Tropic of Capricorn. Instead, individuals experience two “zero shadow” days per year. These days, with the sun directly overhead at solar noon, objects cast a minimal shadow compared to the rest of the year. If you want to see your own shadow at that moment, you have to jump! The exact date for zero shadow days depends on latitude; observers on the Tropic of Cancer (23.5° north of the equator) experience a zero-shadow day on the June solstice, and observers on the Tropic of Capricorn (23.5° south of the equator) get their zero-shadow day on December’s solstice. Observers on the equator experience two zero shadow days, being exactly in between these two lines of latitude; equatorial zero shadow days fall on the March and September equinoxes.

There is some serious science that can be done by carefully observing solstice shadows. In approximately 200 BC, Eratosthenes is said to have observed sunlight shining straight down the shaft of a well during high noon on the solstice, near the modern-day Egyptian city of Aswan. Inspired, he compared measurements of solstice shadows between that location and measurements taken north, in the city of Alexandria. By calculating the difference in the lengths of these shadows, along with the distance between the two cities, Eratosthenes calculated a rough early estimate for the circumference of Earth – and also provided further evidence that the Earth is a sphere!

Are you having difficulty visualizing solstice lighting and geometry? You can build a Suntrack model that helps demonstrate the path the Sun takes through the sky during the seasons. You can find more fun activities and resources like this model on NASA’s Wavelength and Energy activity.

Originally posted by Dave Prosper: June 2022

Last Updated by Kat Troche: April 2024

Simplified Summary

The June solstice happens when the Sun is farthest north from the equator, and the December solstice is when it’s farthest south. During the June one, places outside the tropics have the longest day of the year, and during December’s, they have the shortest. In the Northern Hemisphere, June marks the start of summer, while in the Southern Hemisphere, it’s winter, and it’s the opposite in December. This happens because of the axis on which Earth leans. Because of this tilt, places near the North Pole have continuous daylight in June, while places near the South Pole have continuous darkness. In December, it’s the other way around. This goes on for months, depending on how close you are to the poles. People in the tropics, between the Tropic of Cancer and the Tropic of Capricorn, don’t see as big of a change in daylight. Instead, they have two days a year where shadows almost disappear because the Sun is directly overhead at noon. If you want to see your shadow, you have to jump! The exact days depend on where you are. Around 200 BC, Eratosthenes noticed the Sun was directly overhead on the solstice in one place, comparing that to another place where it wasn’t overhead, and was able to calculate Earth’s size and shape.

In the coming decades, NASA and China intend to send the first crewed missions to Mars. Given the distance involved and the time it takes to make a single transit (six to nine months), opportunities for resupply missions will be few and far between. As a result, astronauts and taikonauts will be forced to rely on local resources to meet their basic needs – a process known as in-situ resource utilization (ISRU). For this reason, NASA and other space agencies have spent decades scouting for accessible sources of liquid water.

Finding this water is essential for future missions and scientific efforts to learn more about Mars’s past, when the planet was covered by oceans, rivers, and lakes that may have supported life. In 2018, using ground-penetrating radar, the ESA’s Mars Express orbiter detected bright radar reflections beneath the southern polar ice cap that were interpreted as a lake. However, a team of Cornell researchers recently conducted a series of simulations that suggest there may be another reason for these bright patches that do not include the presence of water.

The research team was led by Daniel Lalich, a research associate at the Cornell Center for Astrophysics and Planetary Science (CCAPS). She was joined by Alexander G. Hayes, a Jennifer and Albert Sohn Professor, the Director of CCAPS, and the Principal Investigator of the Comparative Planetology & Solar System Exploration (COMPASSE), and Valerio Poggiali, a CCAPS Research Associate. Their paper that describes their findings, “Small Variations in Ice Composition and Layer Thickness Explain Bright Reflections Below Martian Polar Cap without Liquid Water,” appeared on June 7th in the journal Science Advances.

When the first robotic probes began making flybys of Mars in the 1960s, the images they acquired revealed surface features common on Earth. These included flow channels, river valleys, lakebeds, and sedimentary rock, all of which form in the presence of flowing water. For decades, orbiters, landers, and rovers have explored Mars’ surface, atmosphere, and climate to learn more about how and when much of this surface water was lost. In recent years, this has led to compelling evidence that what remains could be found beneath the polar ice caps today.

The most compelling evidence was obtained by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument aboard the Mars Express orbiter. This instrument was designed by NASA and the Italian Space Agency (ASI) to search for water on the Martian surface and down to depths of about 5 km (3 mi). The radar returns indicated that the bright patches could be caused by layered deposits composed of water, dry ice, and dust. These South Polar Layered Deposits (SPLD) are thought to have formed over millions of years as Mars’ axial tilt changed.

Subsequent research by scientists at NASA’s Jet Propulsion Laboratory (JPL) revealed dozens of other highly reflective sites beneath the surface. The implications of these findings were tremendous, not just for crewed missions but also for astrobiology efforts. In addition to being a potential source of water for future missions, it was also theorized that microbial life that once existed on the surface might be found there today. However, the findings were subject to debate as other viable explanations were offered.

While the same bright radar reflections have detected subglacial lakes on Earth (such as Lake Vostok under the East Antarctic Ice Sheet), Mars’s temperature and pressure conditions are very different. To remain in a liquid state, the water would need to be very briny, loaded with exotic minerals, or above an active magma chamber – none of which have been detected. As Lalich said in a recent interview with the Cornell Chronicle:

“I can’t say it’s impossible that there’s liquid water down there, but we’re showing that there are much simpler ways to get the same observation without having to stretch that far, using mechanisms and materials that we already know exist there. Just through random chance you can create the same observed signal in the radar.”

In a previous study, Lalich and his colleagues used simpler models to demonstrate that these bright radar signals could result from tiny variations in the thickness of the layers. These variations would be indiscernible to ground-penetrating radar and could lead to constructive interference between radar waves, producing reflections that vary in intensity and variability – like those observed across the SPLD. For their latest study, the team simulated 10,000 layering scenarios with 1,000 variations in the ice thickness and dust content of the layered deposits.

Their simulations also excluded any of the unusual conditions or exotic materials that would be necessary for liquid water. These simulations produced bright subsurface signals consistent with observations made by the MARSIS instrument. According to Lalich, these findings strongly suggest that he and his colleagues were correct in suspecting radar interference. In essence, radar waves bouncing off of layers too close together for the instrument to resolve may have combined, amplifying their peaks and troughs and appearing much brighter.

The team is not prepared to rule out the possibility that future missions with more sophisticated instruments could find definitive evidence of water. However, Lalich suspects that the case for liquid water (and potential life) on Mars may have ended decades ago. “This is the first time we have a hypothesis that explains the entire population of observations below the ice cap, without having to introduce anything unique or odd. This result where we get bright reflections scattered all over the place is exactly what you would expect from thin-layer interference in the radar. The idea that there would be liquid water even somewhat near the surface would have been really exciting. I just don’t think it’s there.”

If so, future missions may be forced to melt polar ice deposits and permafrost to get drinking water or possibly chemical reactions involving hydrazine (a la Mark Watney). In addition, astrobiology efforts may once again be placed on the back burner as they were when the Viking Landers failed to find conclusive evidence of biosignatures in 1976. But as we’ve learned, Mars is full of surprises. While the results of the Viking biological experiments were disappointing, these same missions provided some of the most compelling evidence that water once flowed on Mars’ surface.

Artist’s impression of water under the Martian surface. If underground aquifers exist, the implications for human exploration and eventual settlement of the Red Planet would be far-reaching. Credit: ESA

Moreover, scientists once suspected that the Red Planet was geologically dead, but data obtained by NASA’s InSight Lander showed that it is actually “slightly alive.” This included evidence that hot magma still flows deep in the planet’s interior and that a massive magma plume still exists beneath the Elysium Planitia region, which may have caused a small eruption just 53,000 years ago (the most recent in Martian history). Perhaps the same will hold true for briny patches of liquid water around the poles and the equatorial region.

With any luck, some of these patches may even house countless microorganisms that could be related to life on Earth. How cool would that be?

Further Reading: Cornell Chronicle, Science Advances

The post Don't Get Your Hopes Up for Finding Liquid Water on Mars appeared first on Universe Today.

What is that light in the sky?

Pandora's Cluster of Galaxies

A US military program led by DARPA is modifying the stimulant drug dextroamphetamine so it can be switched on or off in the brain using near-infrared light, avoiding risks like addiction

A US military program led by DARPA is modifying the stimulant drug dextroamphetamine so it can be switched on or off in the brain using near-infrared light, avoiding risks like addiction

A discarded Japanese rocket was recently imaged up close by the ADRAS-J mission.

A SpaceX rocket suffered a last-second abort during the attempted launch of 22 Starlink internet satellites from Florida on Friday (June 14).

Following a technical error in November 2023, NASA's deep-space explorer has resumed full science operations.

Strangely, the Star Trek: Discovery ship's far-future fate was revealed in 2018 'Short Trek' episode 'Calypso'.