Universe Today

February 23, 2023February 23, 2023 by Matt Williams

How are Mars Rocks Getting “Shocked” by Meteorite Impacts?

Jezero Crater on Mars is the landing site for NASA's Mars 2020 rover. Image Credit: NASA/JPL-Caltech/ASU

On Mars, NASA’s Perseverance rover is busy collecting rock samples that will be retrieved and brought back to Earth by the Mars Sample Return (MSR) mission. This will be the first sample-return mission from Mars, allowing scientists to analyze Martian rocks directly using instruments and equipment too large and cumbersome to send to Mars. To this end, scientists want to ensure that Perseverance collects samples that satisfy two major science goals – searching for signs of life (“biosignatures”) and geologic dating.

To ensure they select the right samples, scientists must understand how rock samples formed and how they might have been altered over time. According to a new NASA study, Martian rocks may have been “shocked” by meteorite impacts during its early history (the Late Heavy Bombardment period). The role these shocks played in shaping Martian rocks could provide fresh insights into the planet’s geological history, which could prove invaluable in the search for evidence of past life on Mars.

February 23, 2023February 24, 2023 by Nancy Atkinson

“The Universe Breakers”: Six Galaxies That are Too Big, Too Early

Images of six candidate massive galaxies, seen 500-700 million years after the Big Bang. One of the sources (bottom left) could contain as many stars as our present-day Milky Way, according to researchers, but it is 30 times more compact. Credit: NASA, ESA, CSA, I. Labbe (Swinburne University of Technology). Image processing: G. Brammer (Niels Bohr Institute’s Cosmic Dawn Center at the University of Copenhagen).

In the first data taken last summer with the Near Infrared Camera (NIRCam) on the new James Webb Space Telescope, astronomers found six galaxies from a time when the Universe was only 3% of its current age, just 500-700 million years after the Big Bang. While its incredible JWST saw these galaxies from so long ago, the data also pose a mystery.

These galaxies should be mere infants, but instead they resemble galaxies of today, containing 100 times more stellar mass than astronomers were expecting to see so soon after the beginning of the Universe. If confirmed, this finding calls into question the current thinking of galaxy formation and challenges most models of cosmology.

February 22, 2023February 23, 2023 by Matt Williams

Clouds of Carbon Dust Seen When the Universe was Less Than a Billion Years Old

This view of nearly 10,000 galaxies is called the Hubble Ultra Deep Field. It shows some galaxies in the early Universe, (which appear as red blobs). Credit: NASA/ESA/HUDF

The Milky Way Galaxy contains an estimated one hundred billion stars. Between these lies the Interstellar Medium (ISM), a region permeated by gas and dust grains. This dust is largely composed of heavier elements, including silicate minerals, ice, carbon, and iron compounds. This dust plays a key role in the evolution of galaxies, facilitating the gravitational collapse of gas clouds to form new stars. This galactic dust is measurable by how it attenuates starlight from distant galaxies, causing it to shift from ultraviolet to far-infrared radiation.

However, the origin of various dust grains is still a mystery, especially during the early Universe when heavier elements are thought to have been scarce. Previously, scientists believed that elements like carbon took hundreds of millions of years to form and could not have existed before about 2.5 billion years after the Big Bang. Using data obtained by the JWST Advanced Deep Extragalactic Survey (JADES), an international team of astronomers and astrophysicists report the detection of carbonaceous grains around a galaxy that existed roughly 1 billion years after the Big Bang.

February 22, 2023February 22, 2023 by Matt Williams

Dust Storms on Mars Generate Static Electricity. What Does This Do to Its Surface?

Artist's impression of the electricity generated by a Martian dust storm. Credit: NASA

Dust storms are a serious hazard on Mars. While smaller storms and dust devils happen regularly, larger ones happen every year (during summer in the southern hemisphere) and can cover continent-sized areas for weeks. Once every three Martian years (about five and a half Earth years), the storms can become large enough to encompass the entire planet and last up to two months. These storms play a major role in the dynamic processes that shape the surface of Mars and are sometimes visible from Earth (like the 2018 storm that ended the Opportunity rover’s mission).

When Martian storms become particularly strong, the friction between dust grains causes them to become electrified, transferring positive and negative charges through static electricity. According to research led by planetary scientist Alian Wang at Washington University in St. Louis, this electrical force could be the major driving force of the Martian chlorine cycle. Based on their analysis, Wang and her colleagues believe this process could account for the abundant perchlorates and other chemicals that robotic missions have detected in Martian soil.

February 22, 2023February 22, 2023 by Nancy Atkinson

Can a Venus Lander Survive Longer Than a Few Minutes?

The first color pictures taken of the surface of Venus by the Venera-13 space probe. Credit: NASA — The first color pictures taken of the surface of Venus by the Venera-13 space probe. The Venera 13 probe lasted only 127 minutes before succumbing to Venus's extreme surface environment. Part of building a longer-lasting Venus lander is figuring out how to power it. Credit: NASA

Sending a lander to Venus presents several huge engineering problems. Granted, we’d get a break from the nail-biting entry, descent and landing, since Venus’ atmosphere is so thick, a lander would settle gently to the surface like a stone settles in water — no sky cranes or retrorockets required.

But the rest of the endeavor is fraught with challenges. The average temperature at the surface is 455 degrees C (850 F), hot enough to melt lead. The mix of chemicals that make up the atmosphere, such as sulfuric acid, is corrosive to most metals. And the crushing atmospheric pressure is roughly equivalent to being 1,500 meters (5,000 ft) under water. These extreme environmental conditions are where metals and electronics go to die; therefore, the few Venus lander missions that have made it to the surface — like the Soviet Venera missions — only lasted two hours or less. Any future landers or rovers will need to have nearly super-hero-type characteristics to endure on the surface of Earth’s evil twin.

But there’s one additional challenge that might be close to being solved: creating batteries that can operate long enough in Venus’ hellish conditions to make a lander mission worth the effort.

February 22, 2023February 22, 2023 by Carolyn Collins Petersen

Astronomers Find a Group of Water-rich Asteroids

Artist's conception of a solar system in formation. It's likely that exoplanet formation around other stars proceeded similarly. Credit: NASA/FUSE/Lynette Cook

If you’ve ever been at sea or visited a seacoast, you probably looked out at the vast expanse of ocean and wondered, “How did all this water get here?” The answer goes back to Earth’s origins some 4.5 billion years ago. In those early times, water-rich planetesimals and other bodies transported water to our still-growing planet. A recent discovery of a previously unknown population of such asteroids between Mars and Jupiter seems to prove that point.

February 22, 2023February 22, 2023 by David Dickinson

Cosmic Conjunction: Jupiter Meets Venus on March 1st

Jupiter vs Venus — Jupiter meets Venus from 2015. Image credit: Roger Hutchison.

The two brightest planets pass less than half a degree apart at dusk during a spectacular conjunction on the night of March 1^st.

It has begun. Once every 12 to 18 months or so, I start fielding “what are those two bright objects in the sky?” questions. They’re none other than the third and fourth brightest natural objects in the sky (behind the Sun and the Moon), the planets Jupiter and Venus. If skies are clear, you can see them get ever closer together from one night to the next, as they meet up during a spectacular conjunction on the night of March 1st/2nd.

February 21, 2023February 22, 2023 by Laurence Tognetti

Meteorites are Contaminated Quickly When They Reach Earth

Image of an Earth-altered sample of the Winchcombe meteorite; scale bar in micrometers. (Credit: University of Glasgow)

On Earth, geologists study rocks to help better understand the history of our planet. In contrast, planetary geologists study meteorites to help better understand the history of our solar system. While these space rocks put on quite the spectacle when they enter our atmosphere at high speeds, they also offer insights into both the formation and evolution of the solar system and the planetary bodies that encompass it. But what happens as a meteorite traverses our thick atmosphere and lands on the Earth? Does it stay in its pristine condition for scientists to study? How quickly should we contain the meteorite before the many geological processes that make up our planet contaminate the specimen? How does this contamination affect how the meteorite is studied?

February 21, 2023February 21, 2023 by Nancy Atkinson

A 500-Meter-Long Asteroid Flew Past Earth, and Astronomers Were Watching

This collage shows six planetary radar observations of 2011 AG5 a day after the asteroid made its close approach to Earth on Feb. 3. With dimensions comparable to the Empire State Building, 2011 AG5 is one of the most elongated asteroids to be observed by planetary radar to date. Credit: NASA/JPL-Caltech

An asteroid the size of the Empire State Building flew past Earth in early February, coming within 1.8 million km (1.1 million miles) of our planet. Not only is it approximately the same size as the building, but astronomers found the asteroid – named 2011 AG5 — has an unusual shape, with about the same dimensions as the famous landmark in New York City.

“Of the 1,040 near-Earth objects observed by planetary radar to date, this is one of the most elongated we’ve seen,” said Lance Benner, principal scientist at JPL who helped lead the observations, in a JPL press release.

This extremely elongated asteroid has a length-to-width ratio of 10:3.

February 20, 2023February 20, 2023 by Matt Williams

All of Jupiter's Large Moons Have Auroras

Artist's concept of aurorae on Ganymede - auroral belt shifting may indicate a subsurface saline ocean. Credit: NASA/ESA

Jupiter is well known for its spectacular aurorae, thanks in no small part to the Juno orbiter and recent images taken by the James Webb Space Telescope (JWST). Like Earth, these dazzling displays result from charged solar particles interacting with Jupiter’s magnetic field and atmosphere. Over the years, astronomers have also detected faint aurorae in the atmospheres of Jupiter’s largest moons (aka. the “Galilean Moons“). These are also the result of interaction, in this case, between Jupiter’s magnetic field and particles emanating from the moons’ atmospheres.

Detecting these faint aurorae has always been a challenge because of sunlight reflected from the moons’ surfaces completely washes out their light signatures. In a series of recent papers, a team led by the University of Boston and Caltech (with support from NASA) observed the Galilean Moons as they passed into Jupiter’s shadow. These observations revealed that Io, Europa, Ganymede, and Callisto all experience oxygen-aurorae in their atmospheres. Moreover, these aurorae are deep red and almost 15 times brighter than the familiar green patterns we see on Earth.