Notices by Fraser Cain (fraser@m.universetoday.com)

Astronomers have announced the discovery of a new asteroid with a non-zero chance of striking the Earth on December 22, 2032. Designated 2024 YR4, the space rock measures between 40 m and 100 m across, which would create regional damage if it struck the Earth. Initial observations estimate it has a 99% chance of passing the Earth safely but a 1% chance of hitting, which gives it a Level 3 designation on the Torino Impact Hazard Scale.

https://www.esa.int/Space_Safety/Planetary_Defence/ESA_actively_monitoring_near-Earth_asteroid_2024_YR4

Mars is cold and dry today, but it was warmer and wetter billions of years ago, with flowing lakes and rivers. The Sun was fainter then, deepening the mystery. Researchers have long believed that atmospheric hydrogen was the key, mixing with carbon dioxide to provide a greenhouse effect. But atmospheric hydrogen is short-lived, so what was replenishing it? A new paper finds that warm periods were driven by crustal hydration, building hydrogen in the atmosphere.

https://seas.harvard.edu/news/2025/01/explaining-persistent-hydrogen-mars-atmosphere

Japanese scientists have found that asteroid samples returned from NASA's OSIRIS-REx mission contain the building blocks of DNA and RNA. The researchers have detected all five nitrogenous bases, which serve as the raw materials for the molecules needed for life. They had already discovered two of these bases in Hayabusa 2 samples from asteroid Ryugu, but Bennu had all five. This shows that the raw materials for life could have been delivered by asteroids.

https://www.eurekalert.org/news-releases/1071865

Astronomers have discovered an exoplanetary system with two gas giant planets that are messing up each other's orbit. One planet has 3.8 Jupiter masses and orbits every 82 days, while the other has 1.4 Jupiter masses. There's also a mini-Neptune world in the system. The two giant planets are locked in a 2:1 orbital resonance, and because of their gravitational interactions, the heavier planet can vary in its orbit by up to 4 days.

https://www.avcr.cz/en/media/press-releases/Violent-dance-of-massive-gas-giant-planets/

Thousands of years ago, a supernova detonated in the constellation Cassiopeia. The flash of light traveled outward, passing through the gas and dust that had been shed by the star before it exploded. Thanks to JWST, astronomers can see how the pulse of radiation continues outward, causing regions of the gas to glow in infrared radiation. The nebula looks like layers of an onion, which could be caused by interstellar magnetic fields interacting with the material.

https://webbtelescope.org/contents/news-releases/2025/news-2025-102

At the end of 2023, there were more than 5,000 satellites orbiting Earth, with 10s of 1000s more on the way. Although individual satellites might be invisible to the unaided eye, their collective light might already be causing a 10% brightness increase in the night sky. Large surveys like Vera Rubin will see frequent satellite trails obscuring important data. And the radio pollution is also increasing with communications satellites. What can be done to restore the sky?

https://arxiv.org/abs/2412.08244

The IceCube Neutrino Observatory in Antarctica is one of the most sensitive instruments ever built, detecting neutrinos from across the Universe. But physicists have hoped that it could also be used to search for evidence of dark matter particles. If dark matter is trapped inside the Earth, the particles would release neutrinos detectable by IceCube. Researchers completed analysis of 10 years of data, but didn't find an excess of neutrinos coming from within the Earth.

https://arxiv.org/abs/2412.12972

Astronomers have found some unusual planetary systems, including planets that orbit around two stars. These are circumbinary planets, and it takes special conditions to be stable. Even if the planets can remain in orbit around both stars, what about their moons? Astronomers haven't found any exomoons yet, but a new paper explores the conditions under which they could form and survive. This is exciting because many would be in the habitable zone of the binary stars.

https://arxiv.org/abs/2412.02847

Humans and robots will retrieve samples from the Moon and bring them back to Earth for study. Instead of finding random locations on the Moon, a new map is helping scientists pinpoint the exact spots that have the greatest potential for study. It's a high-resolution geologic map of the Orientale basin, where an enormous asteroid struck the Moon billions of years ago. The map helps identify parts from the original basin impact melt, which is ideal for sample return.

https://www.psi.edu/blog/new-lunar-maps-can-help-guide-future-sample-return-missions/

Globular clusters are ancient relics of the early Universe, perhaps all that remain from the dwarf galaxies that were torn apart by the Milky Way. They can be 12-13 billion years old, containing 1-2 million stars with several hundred thousand times the mass of the Sun. A new paper shows that globular clusters contain two distinct populations of stars: the primordial ones with normal chemical composition and a second with unusual amounts of heavier elements.

http://www.inaf.it/en/inaf-news/3dview-galactic-globular-clusters

Nine years ago, Blue Origin revealed the plans for their New Glenn rocket, a heavy-lift vehicle with a reusable first stage that would compete with SpaceX for orbital flights. Since that time, SpaceX has launched hundreds of rockets, while Blue Origin has been working mostly in secret on New Glenn. This week, the company rolled out the first prototype first-stage booster to the launch pad. If all goes well, we could see a late November test.

https://www.linkedin.com/company/blue-origin/posts?lipi=urn%3Ali%3Apage%3Ad_flagship3_detail_base%3BKIYtJMi4TM24hZFC1kUiwA%3D%3D

Last year, an intriguing theory was put forward: black holes could be causing dark energy. As more black holes formed in the Universe, the stronger the pressure from dark energy. Now, a survey from the Dark Energy Spectroscopic Instrument (DESI) is strengthening the case for this theory. The first year's data from the survey show that the density of dark energy increases over time in a way that seems to correlate with the number and mass of black holes.

https://www.eurekalert.org/news-releases/1062904

The raw materials for life were likely delivered to the early Earth through a bombardment of asteroids and comets. One example is zinc, which seems to have arrived from across the Solar System—half from beyond the orbit of Jupiter. It appears that the planetesimals that remained far from the Sun and retained their volatile elements were responsible for most of the key chemicals for life delivered to Earth. Those too close to the Sun were stripped of these chemicals.

https://www.cam.ac.uk/research/news/how-did-the-building-blocks-of-life-arrive-on-earth

There are several 3D printers on board the International Space Station, which have been used to print a variety of plastic parts and tools. Now, the newly installed ESA Metal 3D Printer has fashioned a part out of medical-grade stainless steel using lasers. The printer will ultimately complete four different parts with varying shapes to test how microgravity printing compares to Earth-based prints. They'll be returned to Earth for testing.

https://www.esa.int/ESA_Multimedia/Images/2024/09/First_metal_part_3D_printed_in_space

There are large deposits of ice in the Moon's permanently shadowed craters. The challenge is harvesting it for a future lunar base. Solar-powered rovers can't operate in the permanent darkness of the craters. Engineers have developed a design for an ice-mining rover powered by americium-241, which has a half-life of 432 years. This could give the rover enough electricity to operate for decades, heating the ice and trapping water vapor and other volatiles as they escape.

https://www.sciencedirect.com/science/article/pii/S0094576524005459?dgcid=rss_sd_all

The Earth is located inside a 1,000 light-year void called the Local Bubble, which was created by a series of supernovae over the eons. Deposits of iron-60 in deep-sea crust samples tell us that one happened about 5 million years ago, and then another went off 2 million years ago. In a new study, researchers calculate that cosmic radiation levels increased by up to a factor of 30 for about 100,000 years after the explosion, increasing mutation rates in organisms.

https://arxiv.org/abs/2409.12307

Researchers have adapted a computer algorithm that mimics the growth of slime mold to help predict the large-scale structure of the Universe: the cosmic web. As the Universe expands, gravity concentrates galaxies into large clusters, pulling more and more material in over time and opening up vast empty spaces called voids. This is similar to the way slime mold extends to search for concentrations of nutrients. Decaying organic material or gas and dust, it's all the same.

https://newsroom.nmsu.edu/news/nmsu-astronomy-research-uses-slime-mold-to-model-galaxies/s/136ea12b-091a-4240-9de2-389026ef37f3

The Earth has only a single Moon. You might know it as "The Moon." But every now and then, a small asteroid gets too close to Earth and dances with our planet's gravity for a few months or years. Now, astronomers have detected an 11-meter asteroid, designated 2024 PT5, that came within 567,000 km of Earth and will shortly trace a horseshoe path around our planet. It will become a temporary satellite from September 29th until November 25th before it leaves again.

https://iopscience.iop.org/article/10.3847/2515-5172/ad781f

Astronauts Butch Wilmore and Suni Williams will remain on board the International Space Station until February, returning to Earth on a SpaceX Crew Dragon. NASA announced its decision over the weekend, citing concerns about the safety of the Boeing Starliner capsule due to helium leaks and thruster issues. The astronauts will officially join the Expedition 71/72 crew and return home with the rest of the Crew-9 mission in February 2025.

https://www.nasa.gov/news-release/nasa-decides-to-bring-starliner-spacecraft-back-to-earth-without-crew/

The Hubble Space Telescope is in low-Earth orbit and has been repaired multiple times. But spacecraft sent to the Sun-Earth L2 Lagrange Point are beyond the reach of service, whether by robots or astronauts. A new paper proposes trajectories that servicing spacecraft could fly to rendezvous with L2 missions to bring them fresh parts and more propellant to extend their missions indefinitely. They specifically proposed flights to repair Gaia and JWST.

https://www.sciencedirect.com/science/article/pii/S0094576524004715?dgcid=rss_sd_all