Category Archives: astronomy news

The COW in Space

You probably saw all the hoo-rah last week about a COW-like object in space that has astronomers “mystified”, or “baffled”, or even “stumped” (according to the breathless headlines on various news sites. So, what’s behind the headlines that are milking the story for all its worth?

explosion in space

Making a COW

Let’s start with the name of this thing that astronomers observed. The full name of the object is AT2018cow, and you can see the discovery image here. It erupted in or near a galaxy known as CGCG 137-068. That’s located about 200 million light-years away in the constellation Hercules. This shows the location of the “Cow” in the distant galaxy.

Think of it as some kind of eruption in a star, not unlike a supernova or other such outburst. These happen fairly frequently. Astronomers give them complicated names based on what instrument is used to observe them. The name also includes WHEN they’re found. This one was found by the Asteroid Terrestrial-impact Last Alert survey telescope in Hawaii. That’s where the letters AT come from. 2018 is the year it was discovered, and each time there’s one found, it is followed by a letter or sequence of letters. In this case, the sequence came up “cow”.

Astronomers being astronomers, it got shortened to “The Cow” and that led to a lot of really bad puns at last week’s AAS meeting that I won’t repeat here, but some of them were actually funny.

What IS “The COW”?

Now that we’ve got the name out of the way, let’s talk about what this event could have been. I say that because it’s still not clear EXACTLY what happened to cause this bright outburst. That’s going to take some more study and observations. But, there are some leading theories about what The COW outburst was.

First, it could have been the outburst of energy from a black hole shredding a nearby compact star. This is what astronomers call a “tidal disruption event” and could release tremendous amounts of energy that can be detected across large distances. If this happened, then it’s likely that a black hole’s gravity had a close encounter with a star that happened to be passing by. AS they danced past each other, the gravitational pull of the black hole disrupted the star and stretched it into a huge stream of superheated gas. As the gravitational dance continues, the end of the stream whips around like a tail and collides with itself. That creates another superheated cloud of material that would glow quite brightly.

It’s possible that the star was a white dwarf. When it encountered the 100,000-solar mass black hole, that’s what caused all the fireworks. There are still a lot of questions to be answered about this possible cause for The Cow, including its exact location and more details about the star and its black hole dance partner.

An Idea from Supernova Science

Other scientists observing The COW have a different idea, based on their observations from multiple types of instruments. They think that a supernova could have been the culprit that kicked The COW into action. Given the span of observations ranging from gamma rays to radio frequencies, the second team thinks that what they and others observed was the earliest throes of the creation of a compact massive body (like a neutron star or a black hole) as part of a supernova explosion. Nobody’s actually observed one these before, so it would be the first of its kind.

Observing The COW

So, how did astronomers get a glimpse of this thing? First, of course, it showed up in the AT survey. That’s actually a sky survey designed to look for possible asteroids and other impactors that could threaten Earth. It will detect anything that flares up in the sky, and even a distant explosion like The COW qualifies.

After that discovery, astronomers used a multi-wavelength set of observatories to do follow-up observations. Here’s a list:

  • Neil Gehrels Swift Observatory
  • Nuclear Spectroscopic Telescope Array
  • XMM-Newton
  • the Very Large Array
  • INTEGRAL satellite.

To learn more, check out this video from NASA.

These observatories are sensitive to a range of light from radio frequencies to x-rays and gamma-rays. They’re designed to look at fast-occurring energetic objects and events in the universe.

Astronomers will continue to study the data these instruments provided about The COW to figure out just what scenario fits the data best: a gravitational dance between black hole and star or a supernova explosion creating a new high-mass object? Either answer would advance our understanding of stellar physics and evolution. And, as with most science, there’s a healthy amount of debate about the strength of the explosion and other aspects of the event.

Stay tuned! To learn more, check out this video from NASA.

New Horizons, Astronomy, and the Gift of Knowledge

Science: It’s How We Learn about the Universe

In this animated GIF of Kuiper Belt object Ultima Thule made from two images taken 38 minutes apart, the “Thule” lobe is closest to the New Horizons spacecraft. As Ultima Thule is seen to rotate, hints of the topography can be perceived. The images were taken by the Long-Range Reconnaissance Imager (LORRI) at 4:23 and 5:01 Universal Time on January 1, 2019 from respective ranges of 38,000 miles (61,000 kilometers) and 17,000 miles (28,000 kilometers), with respective original scales of 1017 feet (310 meters) and 459 feet (140 meters) per pixel.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The last weekend of 2018 and the first day of the new year brought us some of the most amazing gifts of science in the form of images and data from the New Horizons team as their spacecraft flew past Ultima Thule (2014 MU69). I say these are gifts because what else do you call it when a group of people dedicates their careers and intellects to showing us a tiny world at the edges of the solar system? It is a wonderful thing they gave us: precision measurements, precision flight, and spot-on analysis of what their spacecraft saw and measured. And, they gave it to the world. They handed us knowledge, pure and simple, at a time when scientific knowledge is being dumped on by people who only understand ignorance and fear.

Humans owe our New Horizons team members from around the world a debt of gratitude for the wonders they showed us. Will we give it? I hope so. If you haven’t yet checked out the New Horizons website, look at it periodically. Starting in about a week, as soon as the spacecraft moves out of occultation with the Sun, more data will be streaming down. I’ve been told the highest-resolution images will be headed down within a few weeks.

AAS and Shutdowns

This week, I’m at the American Astronomical Society meeting in Seattle, Washington. There are probably a couple of thousand astronomers here. Unfortunately, many of our most accomplished colleagues are forbidden to be here. They are shut out of their life’s work by a silly government shutdown over a wall our nation doesn’t need and can’t afford. It’s a waste of human talent, made all the worse by the fact that these people (and all government employees) are being forced to live without pay for their work. The effects of the shutdown on people’s jobs and lives are a lousy testament to the shortsighted stupidity of a political party that also denigrates science and knowledge.

Still, science moves on, and we are hearing about very cool things at this meeting. The empty chairs that would have been filled with our NASA colleagues are sad and waiting. And, perhaps the next meeting, we’ll have them back in their rightful places, sharing the science we as taxpayers have funded and want them to do on our behalf.

Astro News

hst image
The powerful wind from the newly formed star at the heart of the Orion Nebula preventing new stars from forming. It created a bubble (black).  At the same time, the wind is pushing molecular gas (color) to the edges. That formed a dense shell around the bubble where future generations of stars can form. Image credits: NASA/SOFIA/Pabst et. al

So, what are hearing about at this meeting? Today, it was exoplanets (with the TESS mission) and also a look at activity in the Orion Nebula, a nearby star formation region. The main story is here, but the gist of it is that the stellar winds flowing off of a newborn star are actually having an effect on nearby clouds of gas and dust. The result is that new stars aren’t forming. This image shows a region nicknamed “The Dragon’s Heart.”

Astronomers ask why star birth can be stopped in its tracks. One idea is that nearby supernova explosions can “quench” star formation. Now, it appears that young stars themselves can stop the births of their siblings, too.

This finding comes from observations by the SOFIA flying observatory. (We were supposed to see this observatory here. However, the shutdown prevented this highly useful observatory from flying here.)

Galaxies and Hubble

Of course, it wouldn’t be an AAS meeting without a Hubble Space Telescope image. This year, it’s the Triangulum Galaxy and we’ll hear more about the science being done on it tomorrow. But, for now, here’s a sneak preview. This gorgeous view comprises 54 Hubble fields that cover an area of sky 19,000 light-years across.

hst image

The image shows the light of nearly 25 million individually resolved stars. It is the largest high-resolution mosaic image of Triangulum ever assembled. You can go over to the site above and explore it in high detail!

This galaxy is a smaller member of the Local Group of galaxies. Since we can see it “face on”, it gives astronomers a good look at spiral galaxy structure. Interestingly, there’s a lot of star formation going on in Triangulum. It turns out to be about 10 times more intense than in the comparable Hubble panorama of the neighboring Andromeda galaxy. There’s a lot to study in this image. I wouldn’t be surprised to see more cool announcements about the mechanics of this galaxy in the years to come. For example, astronomers have a lot to dig into with the galaxy’s spirals and dust lanes. They may learn that this galaxy hasn’t interacted as intensely with its neighbors as others have done. So, stay tuned on this one!

More to Come

The meeting here goes on until Thursday night. There are more sessions on exoplanets, galaxy formation, gravitational waves and other hot topics in the cosmos. It is an exciting time to learn about astronomy!