Universe Today

April 12, 2021April 12, 2021 by Matt Williams

Gaia Finds 12 Examples of Einstein Crosses; Galaxies Being Gravitationally Lensed so we see Them Repeated 4 Times

Credit and : R. Hurt (IPAC/Caltech)/The GraL Collaboration

In 1915, Einstein put the finishing touches on his Theory of General Relativity (GR), a revolutionary new hypothesis that described gravity as a geometric property of space and time. This theory remains the accepted description of gravitation in modern physics and predicts that massive objects (like galaxies and galaxy clusters) bend the very fabric of spacetime.

As result, massive objects (like galaxies and galaxy clusters) can act as a lens that will deflect and magnify light coming from more distant objects. This effect is known as “gravitational lensing,” and can result in all kinds of visual phenomena – not the least of which is known as an “Einstein Cross.” Using data from the ESA’s Gaia Observatory, a team of researchers announced the discovery of 12 new Einstein Crosses.

April 12, 2021April 12, 2021 by Brian Koberlein

Brown Dwarfs can Spin so Fast They Almost Tear Themselves Apart

Comparing the rotation of a brown dwarf with Jupiter and Saturn. Credit: Robert Hurt (IPAC/Caltech)

We tend to image planets as spheres. Held together by gravity, the material of a planet compresses and shifts until gravity and pressure reach a balance point known as hydrostatic equilibrium. Hydrostatic equilibrium is one of the defining characteristics of a planet. If a planet were stationary and of uniform density, then at equilibrium, it would be a perfect sphere. But planets rotate, and so even the largest planets aren’t a perfect sphere.

April 12, 2021April 12, 2021 by Scott Alan Johnston

OSIRIS-REx Did One Last Close Flyby of Asteroid Bennu. It’s Almost Time to Come Home

After more than two years in orbit around asteroid Bennu, NASA’s OSIRIS-REx spacecraft is ready to come home. It’s bringing with it a pristine sample of space rocks that geologists here on Earth are eager to study up close. The sample will arrive in September 2023, but we won’t have to wait nearly that long for new data from OSIRIS-REx. Last week, the probe carried out one final flyby of Bennu, in an effort to photograph the sample collection site. The photographs are being downlinked now, and should be here by midweek.

If you’ve been following the OSIRIS-REx mission, you probably already know why scientists are keen to see these photographs, but if you haven’t, hold on to your hats – it’s a wild story.

April 11, 2021May 7, 2021 by Matt Williams

How’s the Weather in Jezero Crater? According to Perseverance: Cold

On February 18th, 2021, the Perseverance rover landed in the Jezero crater on Mars. Shortly thereafter, it powered up some of the scientific instruments it will use to conduct science operations and search for potential evidence of past life. One such instrument is the Mars Environmental Dynamics Analyzer (MEDA), which turned on for 30 minutes and issued the rover’s first weather report from Mars.

The forecast? Bitter Cold! Basically, the temperature was lower than what you’d expect on a harsh and windy winter’s night here on Earth! According to the data the rover sent back, which was received by mission controllers at 05:25 P.M. EST (08:25 P.M. PST), the local temperature around the Octavia E. Bulter landing in the Jezero crater was -20 °C (- 4 °F) when MEDA started recording, then dropped to -25.6 °C (-14 °F) within 30 minutes.

April 10, 2021April 10, 2021 by Brian Koberlein

Primordial Asteroids That Never Suffered Massive Collisions all Seem to be Larger Than 100 km. Why?

2004 EW95, seen in this artist view, may be a primordial asteroid. Credit: M. Kornmesser/European Southern Observatory

Planetary systems form out of the remnant gas and dust of a primordial star. The material collapses into a protoplanetary disk around the young star, and the clumps that form within the disk eventually become planets, asteroids, or other bodies. Although we understand the big picture of planetary formation, we’ve yet to fully understand the details. That’s because the details are complicated.

April 10, 2021April 10, 2021 by Andy Tomaswick

What Would Raindrops be Like on Other Worlds?

Precipitation is much more widespread throughout that solar system than commonly assumed. Obviously it rains water on Earth. But it snows carbon dioxide on Mars, rains methane on Titan, sulfuric acid on Venus, and could potentially rain diamonds on Neptune. The type of material falling out of the sky is almost as varied as the planets themselves. New research from a team led by Kaitlyn Loftus at Harvard found a similarity for all of the liquid materials that constitute rain throughout the solar system – all of the drops, no matter the material, are roughly the same size.

April 9, 2021April 9, 2021 by Scott Alan Johnston

Jupiter Could Make an Ideal Dark Matter Detector

NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill (wikimedia commons)

So, you want to find dark matter, but you don’t know where to look? A giant planet might be exactly the kind of particle detector you need! Luckily, our solar system just happens to have a couple of them available, and the biggest and closest is Jupiter. Researchers Rebecca Leane (Stanford) and Tim Linden (Stockholm) released a paper this week describing how the gas giant just might hold the key to finding the elusive dark matter.

April 9, 2021April 9, 2021 by Nancy Atkinson

Perseverance Takes a Selfie With Ingenuity. It’s Almost Time to fly

NASA’s Perseverance Mars rover took a selfie with the Ingenuity helicopter, seen here about 13 feet (3.9 meters) from the rover. This image was taken by the WASTON camera on the rover’s robotic arm on April 6, 2021, the 46th Martian day, or sol, of the mission. Credits: NASA/JPL-Caltech/MSSS.

Perseverance is having a proud parent moment in this image, looking like it’s waiting with a child at the bus stop on the first day of school.

April 8, 2021April 8, 2021 by Andy Tomaswick

What are the Best Ways to Search for Technosignatures?

The search for extraterrestrial intelligence (SETI) has long roots in human history. With the advent of modern technologies, scientists were finally able to start scanning the skies for any sign of life. When the search first started back in the 1960s, it focused almost exclusively on trying to detect radio signals. Over the decades, no irrefutable evidence of any artificial radio signals was ever found. Financial support started to drift away from the discipline, and where the money goes so do many scientists.

But more recently, the spike in interest in exoplanet research has breathed new life into the search for intelligent life, now commonly referred to as the search for “technosignatures”. In 2018, NASA sponsored a conference where scientists who were involved with the field came to discuss its current state. That meeting was followed up by a meeting last year sponsored by the Blue Marble Institute, which NASA also helped to sponsor. Now a working paper has come out from the group of SETI scientists that attended the conference. Numerous potential mission ideas to find technosignatures are described in the paper. It’s clear the search for extraterrestrial intelligence isn’t limited just to radio astronomy anymore.

April 8, 2021April 8, 2021 by Brian Koberlein

An Intermediate-Mass Black Hole Discovered Through the Gravitational Lensing of a Gamma-ray Burst

An intermediate mass black hole lenses light around it. Credit: Carl Knox, OzGrav

Black holes come in three sizes: small, medium, and large. Small black holes are of stellar mass. They form when a large star collapses at the end of its life. Large black holes lurk in the centers of galaxies and are millions or billions of solar masses. Middle-sized black holes are those between 100 to 100,000 solar masses. They are known as Intermediate Mass Black Holes (IMBHs), and they are the kind we least understand.