Astronomy

Is baby Skynet already here? We need robust laws now to withstand eliminating humans from nuclear decision-making

The two black holes at the heart of the galaxy OJ 287 are true behemoths with masses of 18.35 billion and 150 million times the mass of our Sun.

Sweltering heat in Greece, ozone-damaging chemicals on the decline and an investigation of what space does to our body are all in this week’s news roundup.

Stay up-to-date with the latest news on the upcoming solar eclipses, including the annular solar eclipse on Oct. 2, 2024.

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Image: Moving the Ariane 6 upper part to the launch pad for first flight

With ESA’s Arctic Weather Satellite due to launch in a few weeks, the satellite is now at the Vandenberg Space Force Base in California being readied for its big day. Once in orbit, this new mission will show how short-term weather forecasts in the Arctic and beyond could be improved.

With his trademark suit-and-tie an anomaly among the primary-colored "Star Trek: Discovery" uniforms of the 32nd century, Dr. Kovich always looked like a man out of time. But who is he, really?

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The first two years of Russia’s war in Ukraine have produced 175 million tons of carbon dioxide

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.

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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.