Category Archives: astronomy

astronomy, astronomy news, astronomy research

The COW in Space

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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.

astronomy, eclipses

Lunar Eclipse Coming

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People are starting to see lurid headlines about the “Super Blood Wolf Moon lunar eclipse” happening this weekend. Specifically, on Sunday night, the Moon will be eclipsed. The phenomenon will be visible throughout North, Central, and South America. It’s entirely normal and nothing to disturb your chakras with or invoke ancient chants during while using crystal suppositories and waving burning herbs in the air. On the upside, there’s no blood involved, but the Moon will appear reddish during totality.

This event is a completely understandable and cool-to-watch phenomenon. It happens as a result of the Moon and Earth circling the Sun in their orbits. The whole eclipse takes a little over five hours from start to finish. If you want to know more about how they work, check out this fabulous page at NASA/JPL. It gives you a step-by-step “narrative” about how the eclipse will proceed.

A lunar eclipse occurs when the orbit of the Earth and Moon line up well enough that the Moon passes behind Earth and through its shadow.

Where and When to Look at the Lunar Eclipse

For people throughout the Western hemisphere, there’s a good chance to see the entire eclipse, or at least part of it starting around 9:36 p.m. Eastern time (in the U.S.). It’ll show up in the western part of the sky. Of course, it all depends on the weather. There are some storms on the horizon for the weekend for parts of the country. For more details on your location and chances of seeing it, check out Time and Date. They have maps and charts available.

Want to watch it live? Check out Griffith Observatory’s live feed Sunday night for a comfortable viewing experience.

Why “Super Blood Wolf” Moon?

Humans LOVE to nickname things. For some, it’s not enough simply to call this event a lunar eclipse. It also comes with some cultural baggage. First, the word “blood” gets used to describe the reddish color the Moon will take on. That’s due to atmospheric conditions that filter out blue light coming from the Sun. The resulting “bath” of reddish photons makes the Moon look red. It’s not really red, though. Plus, astronomers don’t use the term “blood” unless they happen to cut themselves making a sandwich or something.

Second, the term “Wolf Moon” comes from a usage first adopted a few hundred years ago in the U.S. The Natives who inhabited hereand the colonists who came later called it the “Full Wolf Moon”. That’s for the first full Moon in January. They associated it with hungry wolves howling around during the cold winter months. It’s similar in spirit to “Harvest Moon” and other “full moon” names people use throughout the year.

The full Moon we’ll be seeing on Sunday night IS also known as a “supermoon.” That’s because the Moon is slightly closer to Earth in its orbit than usual. That happens and is completely normal and nothing to worry about; the best thing we can do is dress warmly, go outside, and check it out!