What Life on Europa Needs
As the years go by, the chance of Europa hosting life seems to keep going down. But it's not out of contention yet.
The search for life in the universe
As the years go by, the chance of Europa hosting life seems to keep going down. But it's not out of contention yet.
On the surface (you're welcome for the joke), Venus is not even close to being hospitable to life. But that's not the end of the story.
Mars is by far the most Earth-like planet in the solar system…but that's not saying much.
Nuclear Thermal Propulsion (NTP) has stood as a promising potential alternative propulsion technology for decades. Chemical rockets have begun to reach their theoretical maximum efficiency, and their developers have switched their focus to making them cheaper rather than more efficient. NTP should answer that by offering high thrust and specific impulse. NASA's DRACO Program, the standard-bearer for NTP systems, provides a specific impulse of around 900 seconds, about double a traditional chemical rocket, but half that of most ion thrusters. To increase that number even further, researchers at the University of Alabama at Huntsville and The Ohio State University have been working on a novel configuration of NTP called the Centrifugal Nuclear Thermal Rocket (CNTR) that promises almost to double the specific impulse of traditional NTP systems while maintaining similar thrust levels. However, the system has some engineering challenges to overcome, and a new paper coming out in Acta Astronautica describes some incremental progress on making this improved engine a reality.
Sometimes, space enthusiasts blind themselves with techno-optimism about all the potential cool technological things we can do and the benefits they can offer humanity. We conveniently ignore that there are trade-offs: if one group gets to utilize the water available on the lunar surface, that means another group doesn't get to. Recognizing and attempting to come up with a plan to deal with those sorts of trade-offs is the intent of a new paper by Marissa Herron and Therese Jones of NASA's Office of Technology, Policy, and Strategy, as well as Amanda Hernandez of BryceTech, a contractor based out of Virginia.
Whenever scientists present new research showing potential biosignatures on an exoplanet, follow-up articles spread like ripples on a pond. Mainstream media usually runs with it, which shows how the issue captures people's attention. The issue of life on other worlds is a compelling one. This is what happened recently with the exoplanet K2-18b.
We know that planets form in protoplanetary disks, swirling collections of gas and dust that rotate around very young stars. But we don't know all the details, partly because it's difficult to see inside these disks and watch the process unfold. One question astronomers want an answer to concerns ultraviolet radiation. Does extreme ultraviolet radiation disrupt the planet-forming process?
Co-paired stars, or stars that travel together, can provide insights into processes that other stars can't. Differences in their brightness, orbits, and chemical composition can hint at different features, and scientists are beginning to exploit them. A new paper from researchers in Australia, China, the US, and Europe analyzed data to determine if one of those features - specifically the depletion of particular elements in a star - could be a sign that it has formed a planet, or if it ate one.
Mars' oceans, lakes, and rivers are long gone. They've left behind evidence of their time here in river channels, deltas, paleolakes, and other features. The water's existence isn't a mystery, but its whereabouts is. Did it disappear into space, or did it retreat into underground aquifers?
Mars has fascinated us for centuries. Since the invention of the telescope, science fiction writers have mused over its habitability. Its location in the Solar System's habitable zone suggests it could, in theory, support life—despite lacking a global magnetic field and surface water. In a new paper, researchers propose that terraforming Mars is now an achievable goal. They outline methods for warming the planet, releasing pioneer species to build an ecosystem, and improving its atmosphere.
Extreme solar storms are a relatively rare event. However, as more and more of our critical infrastructure moves into space, they will begin to have more and more of an impact on our daily lives, rather than just providing an impressive light show at night. So it's best to know what's coming, and a new paper from an international team of researchers led by Kseniia Golubenko and Ilya Usoskin of the University of Oulu in Finalnd found a massive Extreme Solar Particle Event (ESPE) that happened 12350 years ago, which is now considered to be the most energetic on record.
Just as ice dominates the outer Solar System, blanketing the moons of giant planets and coating objects in the Kuiper Belt and Oort Cloud—astronomers using the James Webb Space Telescope have made a chilly discovery in a distant planetary system. The alien system HD 181327, 155 light-years away harbours significant deposits of both ordinary and crystalline water ice. They detected the ice in regions that are farther away from the star, with the outer area containing as much as 20% water ice.
Veteran NASA scientist Richard H. Stanton describes the results of a multi-year survey of more than 1300 Sun-like stars for optical SETI signals. This survey revealed two fast identical pulses from a Sun-like star about 100 light-years from Earth, that match similar pulses from a different star observed four years ago.
Extraordinary claims require extraordinary evidence. That truism, now known as the "Sagan standard" after science communication Carl Sagan, has been around in some form since David Hume first published it in the 1740s. But, with modern-day data collection, sometimes even extraordinary evidence isn't enough - it's how you interpret it. That's the argument behind a new pre-print paper by Luis Welbanks and their colleagues at Arizona State University and various other American institutions. They analyzed the data behind the recent claims of biosignature detection in the atmosphere of K2-18b and found that other non-biological interpretations could also explain the data.
Most astronomers agree that life is likely common throughout the Universe. While Earth is the only world known to have life, we know that life arose early on our world, and the building blocks of life, including amino acids and sugars, form readily. We also know there are countless worlds in the cosmos that might be home for life. But just because life is likely, that doesn't mean proving it will be easy. Many of the biosignatures we can observe can also have abiotic origins. So how can we be sure? One way is to compare our observations of a habitable world with other worlds in the system.
We tend to think of habitability in terms of individual planets and their potential to host life. But barring outliers like rogue planets with internal heating or icy moons with subsurface oceans created by tidal heating, it's exoplanet/star relationships that generate habitability, not individual planets. New research emphasizes that fact.
One of the unanswered questions in astronomy is just how supermassive black holes grew so big, so quickly. A team of astronomers have tried to answer this question by searching for actively feeding supermassive black holes (aka quasars) as a way to measure how much material material they are actually accumulating. They studied nebulae near the quasars that light up with the quasar is releasing radiation and found that many of the more distant quasars have only been active for a few hundred thousand years, not long enough to grow to the size we see today.
The Fermi Paradox presents us with a striking contradiction: despite the high probability of numerous civilizations existing throughout the Universe, we've encountered no evidence or communication from any alien intelligence. A new paper just published calculates that we should have a 99% chance of detecting at least one signal from another civilisation—assuming they survive for several hundred years and could be distributed anywhere across the Milky Way galaxy. This calculation further deepens the mystery of our apparent cosmic solitude.
If astronomy has a Holy Grail, it's another habitable world. To find one, NASA is working with partners to develop the Habitable Worlds Observatory (HWO). The HWO would be the first telescope built to detect Earth-like planets around Sun-like stars. China is building the Closeby Habitable Exoplanet Survey (CHES), and new research shows that by working together, HWO and CHES would amplify their results.
What new technologies or methods can be developed for more efficient in-situ planetary subsurface analyses? This is what a recent study presented at the 56th Lunar and Planetary Science Conference hopes to address as a team of researchers investigated how a novel instrument called OptiDrill could fill existing technological voids regarding the sampling and collection of regolith (top dust layer) and subsurface samples on a myriad of planetary bodies throughout the solar system.