Astronomy Archives

April 7, 2020April 7, 2020 by Paul M. Sutter

Decaying Dark Matter Should be Visible Here in the Milky Way as a Halo Around the Galaxy

A simulated image of what the X-ray emission from dark matter might be. Image credit: Christopher Dessert, Nicholas L. Rodd, Benjamin R. Safdi, Zosia Rostomian (Berkeley Lab), based on data from the Fermi Large Area Telescope

Astronomers are very sure that dark matter exists, but they’re not sure at all what it’s made of.

The problem is that it isn’t just dark, it’s invisible. As far as we know, dark matter doesn’t emit light, absorb light, reflect light, refract light, scatter light, diffract light, or really have anything to do with light at all. This makes it hard to study. We know that dark matter exists, however, through its gravitational effects. Even though it’s invisible, it still has mass, and so the dark matter in our universe (which, by the way, makes up 85% of all the mass in the cosmos) can affect the motions of normal (or light-interacting) matter, like stars and galaxies.

April 4, 2020April 4, 2020 by Paul M. Sutter

Astronomers are hoping to see the very first stars and galaxies in the Universe

The epoch of reionization was when light from the first stars could travel through the early Universe. At this time, galaxies began assembling, as did black holes. Why did some early galaxies have ancient stars? That's a question JWST will help answer. Credit: Paul Geil & Simon Mutch/The University of Melbourne

Sometimes it’s easy being an astronomer. When your celestial target is something simple and bright, the game can be pretty straightforward: point your telescope at the thing and just wait for all the juicy photons to pour on in.

But sometimes being an astronomer is tough, like when you’re trying to study the first stars to appear in the universe. They’re much too far away and too faint to see directly with telescopes (even the much-hyped James Webb Space Telescope will only be able to see the first galaxies, an accumulation of light from hundreds of billions of stars). To date, we don’t have any observations of the first stars, which is a major bummer.

April 3, 2020April 3, 2020 by David Dickinson

New Find Shows Uranus Loses Atmosphere to its Magnetic Field

You may never look at Uranus the same way again. It’s always worth combing through data from old space missions for new finds.

NASA’s researchers at the Goddard Space Flight Center recently did just that, looking at Voyager 2’s lone encounter with the planet Uranus to uncover an amazing find, as the planet seems to be losing its atmosphere to it’s lop-sided magnetic field at a high rate. The finding was published in a recent edition of Geophysical Research: Letters.

April 2, 2020April 2, 2020 by Evan Gough

Astronomers Define the “Really Habitable Zone”. Planets Capable of Producing Gin and Tonic

Gin and tonic. Image Credit: By NotFromUtrecht - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8529628

A hospitable star that doesn’t kill you with deadly flares. A rocky planet with liquid water and an agreeable climate. Absence of apocalyptic asteroid storms. No pantheon of angry, vengeful, and capricious gods. These are the things that define a habitable planet.

Now some scientists are adding one more criterion to the list: gin and tonic.

April 1, 2020April 1, 2020 by Matt Williams

Five Snapshots of how the Earth Looked at Key Points in its History Could Help us Find Habitable Exoplanets

Exoplanet Kepler 62f would need an atmosphere rich in carbon dioxide for water to be in liquid form. Artist's Illustration: NASA Ames/JPL-Caltech/T. Pyle

In the past few decades, astronomers have confirmed the existence of thousands of planets beyond our Solar System. Over time, the process has shifted from discovery to characterization in the hopes of finding which of these planets are capable of supporting life. For the time being, these methods are indirect in nature, which means that astronomers can only infer if a planet is inhabitable based on how closely it resembles Earth.

To aid in the hunt for “potentially habitable” exoplanets, a team of Cornell researchers recently created five models that represent key points in Earth’s evolution. These “snapshots” of what Earth looked like during various geological epochs could greatly enhance the search for extra-terrestrial life by providing a more complete picture of what a life-bearing planet could look like.

April 1, 2020April 1, 2020 by Evan Gough

This Galaxy Has Only One Spiral Arm

NGC 4618, the one-armed galaxy. Image Credit: ESA/Hubble & NASA, I. Karachentsev; CC BY 4.0

There are all kinds of odd things in the sky. Things that defy our naming conventions, and our attempts to understand them. For instance, NGC 4618, the one-armed galaxy.

March 31, 2020April 3, 2020 by Matt Williams

SpaceX Almost Ready to Start Testing its Third Starship Prototype. Let’s Hope it Doesn’t Explode

For almost a year now, SpaceX has been building a series of Starship prototypes that will test how the system fares when launched to orbit. Coming on the heels of successful hop tests with the Starship Hopper, these tests will validate the spacecraft and its Raptor engines in space. Unfortunately, the company has encountered some hiccups with these prototypes, where the first two exploded during pressure testing.

The first prototype, Starship Mk.1, exploded on the launchpad on November 20th, 2019, during a cryogenic loading test that sent its nose cone flying. The second prototype, SN1, also exploded during a pressure test on the evening of Feb. 28th, 2020, causing the fuselage to jump several meters in the air before hitting the ground and exploding again. Undeterred, Musk recently shared images of the components for the SN3 prototype undergoing assembly.

March 31, 2020March 31, 2020 by Evan Gough

This Galaxy is the Very Definition of “Flocculent”

This image taken by the NASA/ESA Hubble Space Telescope shows the galaxy NGC 4237. Located about 60 million light-years from Earth in the constellation of Coma Berenices (Berenice's Hair), NGC 4237 is classified as a flocculent spiral galaxy. This means that its spiral arms are not clearly distinguishable from each other, as in “grand design” spiral galaxies, but are instead patchy and discontinuous. This gives the galaxy a fluffy appearance, somewhat resembling fluffed cotton. Image Credit: ESA/Hubble & NASA, P. Erwin et al.

I know you’re Googling “flocculent” right now, unless you happen to be a chemist, or maybe a home brewer.

You could spend each day of your life staring at a different galaxy, and you’d never even come remotely close to seeing even a tiny percentage of all the galaxies in the Universe. Of course, nobody knows for sure exactly how many galaxies there are. But there might be up to two trillion of them. If you live to be a hundred, that’s only 36,500 galaxies that you’d look at. Puts things in perspective.

March 30, 2020March 30, 2020 by Matt Williams

How were Supermassive Black Holes Already Forming and Releasing Powerful Jets Shortly After the Big Bang?

A supermassive black hole has been found in an unusual spot: an isolated region of space where only small, dim galaxies reside. Image credit: NASA/JPL-Caltech — A team of astronomers from South Africa have noticed a series of supermassive black holes in distant galaxies that are all spinning in the same direction. Credit: NASA/JPL-Caltech

In the past few decades, astronomers have been able to look farther into the Universe (and also back in time), almost to the very beginnings of the Universe. In so doing, they’ve learned a great deal about some of the earliest galaxies in the Universe and their subsequent evolution. However, there are still some things that are still off-limits, like when galaxies with supermassive black holes (SMBHs) and massive jets first appeared.

According to recent studies from the International School for Advanced Studies (SISSA) and a team of astronomers from Japan and Taiwan provide new insight on how supermassive black holes began forming just 800 million years after the Big Bang, and relativistic jets less than 2 billion years after. These results are part of a growing case that shows how massive objects in our Universe formed sooner than we thought.

March 27, 2020March 27, 2020 by Evan Gough

Are the Gaps in These Disks Caused by Planets?

Are baby planets responsible for the gaps and rings we’ve spotted in the disks that surround distant, young stars? Image Credit: C. Pinte et al, 2020

Astronomers like observing distant young stars as they form. Stars are born out of a molecular cloud, and once enough of the matter in that cloud clumps together, fusion ignites and a star begins its life. The leftover material from the formation of the star is called a circumstellar disk.

As the material in the circumstellar disk swirls around the now-rotating star, it clumps up into individual planets. As planets form in it, they leave gaps in that disk. Or so we think.