Universe Today

January 20, 2024January 20, 2024 by Brian Koberlein

Life on Earth Uses Water as a Solvent. What are Some Other Options for Life as We Don't Know it?

A near-infrared view of Titan showing its glinting seas. Credit: NASA/JPL-Caltech/University of Arizona/University of Idaho

There is a vast menagerie of potentially habitable worlds in the cosmos, which means the Universe could be home to a diversity of life beyond what we can imagine. Creatures built on silicon rather than carbon, or organisms that breathe hydrogen instead of oxygen. But regardless of how strange and wondrous alien life may be, it is still governed by the same chemistry as life on Earth, and that means it needs a chemical solvent.

January 19, 2024January 19, 2024 by Matt Williams

Future Mars Helicopters Could Explore Lava Tubes

The circular black features in this 2007 figure are caves formed by the collapse of lava tubes on Mars. Image credit: NASA/JPL-Caltech/ASU/USGS

The exploration of Mars continues, with many nations sending robotic missions to search for evidence of past life and learn more about the evolution of the planet’s geology and climate. As of the penning of the article, there are ten missions exploring the Red Planet, a combination of orbiters, landers, rovers, and one helicopter (Ingenuity). Looking to the future, NASA and other space agencies are eyeing concepts that will allow them to explore farther into the Red Planet, including previously inaccessible places. In particular, there is considerable interest in exploring the stable lava tubes that run beneath the Martian surface.

These tubes may be a treasure trove of scientific discoveries, containing water ice, organic molecules, and maybe even life! Even crewed mission proposals recommend establishing habitats within these tubes, where astronauts would be sheltered from radiation, dust storms, and the extreme conditions on the surface. In a recent study from the University Politehnica Bucuresti (UPB), a team of engineers described how an autonomous Martian Inspection Drone (MID) inspired by the Inginuity helicopter could locate, enter, and study these lava tubes in detail.

January 19, 2024January 23, 2024 by Alan Boyle

Japan’s Moon Lander Touches Down, But Power Problem Mars Its Mission

Illustration: SLIM lander on the moon — An artist's conception shows Japan's SLIM lander on the moon. Credit: ISAS/JAXA

Update for Jan. 21: The Japan Aerospace Exploration Agency shut down its moon lander to conserve battery power, but says the lander might be recharged and revived if sunlight hits the solar cells at the right angle.

Japan has become the fifth nation to land a functioning robot on the moon, but the mission could fall short of complete success due to a problem with the lander’s power-generating solar cells.

January 19, 2024January 19, 2024 by Andy Tomaswick

What Future Propulsion Technologies Should NASA Invest In?

Researchers consistently complain about how difficult it is to fund breakthrough research. Most funding agencies, especially governmental ones, think funding incremental, evolutionary technological steps is the way to go, as it has the most significant immediate payback. But longer-term, higher-risk research is necessary to provide those incremental steps 20-30 years in the future. And in some cases, they are required to underpin completely new things that other researchers want to do.

January 19, 2024January 19, 2024 by Carolyn Collins Petersen

Diamond Rain on Ice Giants Could Influence Their Magnetic Fields

Scientists created a model to explain how diamond rain falls inside Uranus and Neptune and messes with their magnetic fields. Courtesy SLAC.

Imagine Jupiter with a diamond core the size of Earth. That’s what science fiction author Arthur C. Clarke described in his novel (and movie) 2010: Odyssey 2. Now, imagine the same thing, but at Uranus and Neptune. In addition to a possible diamond core, diamond rain fills the interior. Scientists at the U.S. Department of Energy’s SLAC National Accelerator Laboratory think they know how these diamonds form on ice-giant planets.

January 19, 2024January 19, 2024 by Evan Gough

Is this the Lightest Black Hole or Heaviest Neutron Star?

An international team of astronomers have found a new and unknown object in the Milky Way that is heavier than the heaviest neutron stars known and yet simultaneously lighter than the lightest black holes known. Image Credit: University of Manchester/Max Planck Institutue for Radio Astronomy

About 40,000 light-years away, a rapidly spinning object has a companion that’s confounding astronomers. It’s heavier than the heaviest neutron stars, yet at the same time, it’s lighter than the lightest black holes. Measurements place it in the so-called black hole mass gap, an observed gap in the stellar population between two to five solar masses. There appear to be no neutron stars larger than two solar masses and no black holes smaller than five solar masses.

January 19, 2024January 19, 2024 by Evan Gough

Astronomers See Massive Stars Forming Together in Multiple Star Systems

This false-color image of the massive star formation region G333.23–0.06 came from data obtained with the ALMA radio observatory. The insets show regions where researchers detected multiple systems of protostars. The star symbols indicate the location of each newly forming star. Image Credit: S. Li, MPIA / J. Neidel, MPIA Graphics Department / Data: ALMA Observatory

All stars form in giant molecular clouds of hydrogen. But some stars are extraordinarily massive; the most massive one we know of is about 200 times more massive than the Sun. How do these stars gain so much mass?

Part of the answer is that they form in multiple star systems.

January 19, 2024January 19, 2024 by Mark Thompson

Early Galaxies Looked Nothing Like What We See Today

Though an estimated 100 million black holes roam among the stars in our Milky Way galaxy, astronomers have never identified an isolated black hole – until now. Following six years of meticulous observations, NASA’s Hubble Space Telescope has provided, for the first time ever, strong evidence for a lone black hole plying interstellar space. The black hole that was detected lies about 5,000 light-years away, in the Carina-Sagittarius spiral arm of our galaxy. However, its discovery allows astronomers to estimate, statistically, that the nearest isolated black hole to Earth might be as close as 80 light-years. Black holes are born from rare, monstrous stars (less than one-thousandth of the galaxy’s stellar population) that are at least 20 times more massive than our Sun. These stars explode as supernovae, and the remnant core is crushed by gravity into a black hole. Because the self-detonation is not perfectly symmetrical, the black hole may get a kick, and go careening through our galaxy like a blasted cannonball. Hubble can’t photograph the wayward black hole because it doesn’t emit any light, but instead swallows all radiation due to its intense gravitational pull. Instead, Hubble measurements capture the ghostly gravitational footprint of how the stealthy black hole warps space, which then deflects starlight from anything that momentarily lines up exactly behind it. Ground-based telescopes, which monitor the brightness of millions of stars in the rich star fields in the direction of the central bulge of our Milky Way, look for the tell-tale sudden brightening of one of them when a massive object passes between us and the star. Then Hubble follows up on the most interesting such events. Kailash Sahu of the Space Telescope Science Institute in Baltimore, Maryland, along with his team, made the discovery in a survey designed to find just such isolated black holes. The warping of space due to the gravity of a foreground object passing in front of a star located far behind it will momentarily bend and amplify the light of the background star as it passes in front of it. The phenomenon, called gravitational microlensing, is used to study stars and exoplanets in the approximately 20,000 events seen so far inside our galaxy. The signature of a foreground black hole stands out as unique among other microlensing events. The very intense gravity of the black hole will stretch out the duration of the lensing event for over 200 days. Also, If the intervening object was instead a foreground star, it would cause a transient color change in the starlight as measured because the light from the foreground and background stars would momentarily be blended together. But no color change was seen in the black hole event. Next, Hubble was used to measure the amount of deflection of the background star’s image by the black hole. Hubble is capable of the extraordinary precision needed for such measurements. The star’s image was offset from where it normally would be by two milliarcseconds. That’s equivalent to measuring the diameter of a 25-cent coin in Los Angeles as seen from New York City. This astrometric microlensing technique provided information on the mass, distance, and velocity of the black hole. The amount of deflection by the black hole’s intense warping of space allowed Sahu’s team to estimate it weighs seven solar masses. The isolated black hole is traveling across the galaxy at 90,000 miles per hour (fast enough to travel from Earth to the moon in less than three hours). That’s faster than most of the other neighboring stars in that region of our galaxy. “Astrometric microlensing in conceptually simple but observationally very tough,” said Sahu. “It is the only technique for identifying isolated black holes.” When the black hole passed in front of a background star located 28,000 light-years away in the galactic bulge, the starlight coming toward Earth was amplified for a duration of 265 days as the black hole passed by. However, it took several years of Hubble observations to follow how the background star’s position appeared to be deflected by the bending of light by the foreground black hole. The existence of stellar-mass black holes has been known since the early 1970’s, but all of them—until now—are found in binary star systems. Gas from the companion star falls into the black hole, and is heated to such high temperatures that it emits X rays. About two dozen black holes have had their masses measured in X-ray binaries through their gravitational effect on their companions. Black hole masses in X-ray binaries inside our galaxy range from 5 to 20 solar masses. Black holes detected in other galaxies by gravitational waves from mergers between black holes and companion objects have been as high as 90 solar masses. “Detections of isolated black holes will provide new insights into the population of these objects in our Milky Way,” said Sahu. He expects that his program will uncover more free-roaming black holes inside our galaxy. But it is a needle-in-a-haystack search. The prediction is that only one in 1500 microlensing events are caused by isolated black holes. NASA’s upcoming Nancy Grace Roman Space Telescope will discover several thousand microlensing events out of which many are expected to be black holes, and the deflections will be measured with very high accuracy. In a 1916 paper on general relativity, Albert Einstein predicted that his theory could be tested by observing the sun’s gravity offsetting the apparent position of a background star. This was tested by astronomer Arthur Eddington during a solar eclipse on May 29, 1919. Eddington measured a background star being offset by 2 arc seconds, validating Einstein’s theories. Both scientists could hardly have imagined that over a century later this same technique would be used – with unimaginable precision of a thousandfold better — to look for black holes across the galaxy.

Talk to anyone about galaxies and it often conjurs up images of spiral or elliptical galaxie. Thanks to a survey by the James Webb Space Telescope it seems the early Universe was full of galaxies of different shapes. In the first 6 billion years up to 80% of the galaxies were flat, surfboard like. But that’s not it, there were others like pool noodles too, yet why they looked so different back then is a mystery.

January 19, 2024January 19, 2024 by Brian Koberlein

M87*'s Event Horizon Image. One Year Later

The elliptical galaxy M87 seen by various telescopes. Credit: NASA's Scientific Visualization Studio/M.SubbaRao & NASA/CXC/SAO/A.Jubett

Fifty-five million light years from Earth there is a massive elliptical galaxy known as Messier 87, or M87 for short. It was cataloged by Charles Messier in the 1700s, along with 102 other fuzzy objects in the sky that were definitely not comets. It was confirmed to be a galaxy in the early 1900s, and by the mid-twentieth century, it was known to be a powerful radio source. But these days it is most widely known for the supermassive black hole deep in its core. Called M87*, it is the first black hole directly observed by astronomers. The first image of M87* was released in 2019, and was based on observations taken by the Event Horizon Telescope (EHT) in 2017. Now a new image based on 2018 data has been released. The similarities and differences between the two images tell us a great deal about M87* and black holes in general.

January 19, 2024January 19, 2024 by Nancy Atkinson

This Strange-Looking Galaxy is Actually Two. And They're Merging

This NASA/ESA Hubble Space Telescope image features Arp 122, a peculiar galaxy that in fact comprises two galaxies – NGC 6040, the tilted, warped spiral galaxy and LEDA 59642, the round, face-on spiral – that are in the midst of a collision. ESA/Hubble & NASA, J. Dalcanton, Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA Acknowledgement: L. Shatz

This strange-looking galaxy seems to be a spiral with a long tidal tail stretching away. It’s known as Arp 122, and it’s actually not just one galaxy, but two separate galaxies. NGC 6040 is the warped spiral galaxy seen edge-on, while LEDA 59642 is the round, face-on spiral. The two are colliding about 540 million light-years from Earth, and it gives us a preview of the Milky Way’s future collision with Andromeda.

This image was taken by the venerable Hubble Space Telescope

What will Arp 122 look like when the merger is complete? We’ll try to keep you posted, but this ongoing merger will take hundreds of millions of years, so be patient.