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

Returning to Earth is a free ride, using the friction of the atmosphere to shed enormous velocity. But re-entering spacecraft build up high temperatures on their exteriors, which can destroy them (remember the Columbia disaster)? A team of engineers is investigating how a trick of nature—sweating—could work during spacecraft re-entry. A spacecraft would create a layer of gas on its surface that would cool the spacecraft and prevent direct contact with the hot gases.

https://www.eurekalert.org/news-releases/1082474

A mystery in astronomy is how supermassive black holes grew so big, so quickly. Astronomers have looked for quasars, actively feeding supermassive black holes, as a way to measure how much new material they’re accumulating, contributing to their growth. They studied nebulae near the quasars that light up when the quasar is releasing radiation and found that many of the farthest quasars have only been active for a few hundred thousand years, not long enough to grow.

https://arxiv.org/abs/2505.00080

Earth has only one moon, the Moon, but it does have smaller objects that visit the planet, complete a few orbits, and then head off into space again. Astronomers have detected four of these objects so far and performed spectroscopic analyses on them, analyzing their surface composition. They found that some of these minimoons have a composition that's very similar to the Moon, pointing to it as a major source of these temporary satellites and not the asteroid belt.

https://arxiv.org/abs/2504.17985

Helium-3 is a rare isotope emitted by the Sun, and it's very scarce in the Solar System. It's estimated that there's only one He3 atom for every 2,500 He4 atoms. But solar jets can boost the amount of He3 to 10,000 times its usual concentration. ESA's Solar Orbiter mission was recently bathed in He3, recording a 200,000-fold increase of the rare isotope because it was accelerated to higher speeds than other heavier elements by a jet emerging from a coronal hole.

https://www.swri.org/newsroom/press-releases/swri-scientists-source-solar-emissions-largest-ever-concentration-of-rare-helium-isotope

Supermassive black holes can emit powerful jets that stretch out into the cosmos, but the less massive stellar black holes can form jets too, generating beams of ionized gas that shoot outward at nearly the speed of light. Now, astronomers think they understand the underlying mechanism that generates these jets. They occur when the inner radius of the accretion disk suddenly decreases and reaches the closest point that matter can orbit without falling in.

https://www.eurekalert.org/news-releases/1079925

Gamma-ray bursts are some of the most powerful explosions in the Universe, briefly outshining the combined light of their entire galaxies. A team of astronomers has figured out a clever technique to use the light from gamma-ray bursts as bright lights that allow them to map out the large-scale structure of the Universe at different ages after the Big Bang. They found that the Universe might be less uniform at large scales than previously thought.

https://arxiv.org/abs/2504.05354

Astronomers are searching for intermediate-mass black holes, in between the stellar and supermassive varieties. Recently, a group of researchers announced the discovery of a high-velocity star rocketing out of the globular cluster M15, ejected about 20 million years ago and hurtling at 550 km/s on an escape trajectory from the Milky Way. The astronomers think this could have been caused by a three-body interaction with an intermediate-mass black hole.

https://www.eurekalert.org/news-releases/1079611

It's easy to measure the rotation rate of terrestrial planets, but the gas and ice giant planets are much more difficult, where you can't measure features on their surface directly. Instead, astronomers have relied on indirect methods, like measuring the rotation of their magnetic fields. New observations from Hubble have refined the rotation rate of Uranus with unprecedented precision, using an extremely clever method: watching the auroras complete one rotation.

https://www.esa.int/ESA_Multimedia/Images/2025/04/Hubble_helps_determine_Uranus_rotation_rate_with_unprecedented_precision

NASA's Perseverance was scanning the rim of Jezero Crater when it spotted a Martian dust devil overtake and consume another smaller one. The rover was about a kilometer away from the larger dust devil, which was about 65 meters wide. The smaller one was about 5 meters wide. This isn't Perseverance's first encounter with dust devils. It's seen clusters dancing around it and even captured audio of a dust devil on Mars for the first time.

https://www.nasa.gov/missions/mars-2020-perseverance/perseverance-rover/perseverance-rover-witnesses-one-martian-dust-devil-eating-another/

All eyes are on the Moon's south polar region, where permanently shadowed craters are protecting pockets of water ice. The ShadowCam imager, flying on Korea's Pathfinder Lunar Orbiter, can peer into these craters better than any other instrument. Planetary scientists used a machine learning algorithm to identify over a billion impact craters near the south pole, inside the shadowed craters, each larger than 16 meters in diameter.

https://www.hou.usra.edu/meetings/lpsc2025/pdf/1775.pdf

It's widely accepted that the Moon formed when a Mars-sized planet crashed into the Earth, creating a stream of debris that coalesced into the Moon. But when did it happen? Current estimates range from 4.52 to 4.35 billion years ago, but a new presentation at LPSC pushes that timeline much earlier. They analyzed some of the oldest lunar crustal rocks and calculated that they formed just 65 million years after the Solar System formed, much earlier than previous estimates.

https://www.hou.usra.edu/meetings/lpsc2025/pdf/2111.pdf

Evidence is growing that dark energy's influence on the expansion rate of the universe has been changing over time. A range of space and ground-based observatories are coming online to measure the expansion rate across the universe's history, but a supercomputer has crunched the data and found similar results. Researchers compared two large-scale simulations of the universe, one with constant dark energy and one where it varies, and that better matched the observations.

https://www.anl.gov/article/argonne-team-uses-aurora-supercomputer-to-investigate-potential-dark-energy-breakthrough#:~:text=While%20scientists%20continue%20to%20validate,Global%20Physics%20Summit%20this%20week.

This week, I decided to remove all ads from everything on Universe Today. And I couldn't be happier.

https://www.youtube.com/watch?v=H0uKlAHcUGk

Good news! It turns out that safely landing on the Moon isn't impossible. After a string of lunar landers failed, Firefly's Blue Ghost touched down on March 2nd in Mare Crisium on the near side of the Moon, becoming the first privately built lander to complete this feat. Blue Ghost is carrying ten experiments, which will operate over the next two weeks before the lunar night sets in. It will take the first images of a total solar eclipse seen from the Moon.

https://www.nasa.gov/news-release/touchdown-carrying-nasa-science-fireflys-blue-ghost-lands-on-moon/

Neutrinos are produced by fusion reactions in the Sun, passing effortlessly through its dense interior. Different reactions produce neutrinos with different energies, and researchers think this could be a way they could probe the interior of the Sun. Various Earth-based solar neutrino observatories are catching neutrinos hurled by the Sun, which can be compared to those produced by nuclear reactors. This will allow astronomers to build up an interior map of the Sun.

https://arxiv.org/abs/2502.17546

Magnetars are a type of neutron star with the most powerful magnetic fields in the universe. They're formed by the death of massive stars, like pulsars and other neutron stars. So, what creates such intense magnetic fields? Thanks to a new simulation, astronomers have discovered that a magnetar probably forms when material ejected by the supernova explosion falls back down onto the star's surface, amplifying its dynamo effect.

https://www.unige.ch/medias/en/2025/aux-origines-des-etoiles-mega-magnetiques

Until someone tells them otherwise, engineers at NASA are continuing to prepare for the upcoming Artemis II mission, where 4 astronauts will take an Apollo 8-style flight around the Moon in an Orion Capsule and return to Earth. As part of this mission, technicians fully stacked the twin Space Launch System solid rocket boosters in the Vehicle Assembly Building. They started stacking the twin rockets in late November 2024, completing them on February 19th.

https://www.nasa.gov/image-article/artemis-ii-rocket-booster-stacking-complete/

Astronomers have discovered a hypervelocity star blasting through the Milky Way at 540 km/s. These have been seen before, but what makes this special is a super-Neptune exoplanet in orbit around the star. It's possible that the star was part of a binary system that came too close to the black hole at the center of the Milky Way, which stripped away one of the pair, hurling the other away at high velocity. Amazingly, it hung onto its planet through the process.

https://www.nasa.gov/universe/nasa-scientists-spot-candidate-for-speediest-exoplanet-system/

The Japanese lunar mission Hakuto-R turned its cameras back to Earth to capture an image of our home planet. The very center of the image is Point Nemo, the most remote place on Earth, 2,688 km from anywhere else on Earth. The image was taken by the Resilience rover, which is similar to the first Hakuto-R mission that crashed on the lunar surface in April 2023. The rover will scoop up samples of lunar regolith for study, and the lander has other science experiments.

https://x.com/ispace_inc/status/1884558826558607740

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