Reporters Don't Understand Black Holes

Black holes are really cool, of course, and the recent news that they've found the smallest black hole yet is certainly interesting (just 3.8 times the mass of our own Sun). I just wish they could write an article about it that didn't have so many mistakes! Here's the article. And now for the mistakes....

It would likely be stronger than bigger black holes found at the centers of galaxies. Shaposhnikov said if someone ventured too close to J1650, its gravity would "stretch your body into a strand of spaghetti."

J1650 is the "name" of the black hole, Shaposhnikov is one of the NASA scientists who discovered it. His quote is fine - indeed, if you get too close to any black hole you would get stretched long and thin like a strand of spaghetti. It's the first sentence I have a problem with. The author of this article, Maggie Fox (who is, at best, a science reporter, and not a scientist), never explains what she means by this black hole being stronger than others. The strength of a black hole depends only on its mass, not anything else. Therefore this should be the weakest black hole ever found, and certainly not stronger than the super-massive black holes found at the centers of galaxies - those are millions of times more massive than our Sun.

Shaposhnikov and his Goddard colleague Lev Titarchuk used NASA's Rossi X-ray Timing Explorer satellite and a new method to estimate the size of the black hole, found in a system in the southern constellation Ara, in our own Milky Way Galaxy.

This is misleading - the size of a black hole is actually infinitesimally small, at least that's what our current knowledge of physics tells us. You can't give the size of the black hole itself, but you can talk about the size of its event horizon, which is the point of no return for black holes - if anything crosses a black hole's event horizon, that object will never get out. The size of a black hole's event horizon is given by a fairly simple equation, and is called the Schwarschild Radius, after the scientist who first did the calculation. What these two scientists likely did was first find an object and determine it's mass by watching gases that orbit the object. Knowing its mass alone does not tell you whether or not the object is a black hole, however. That's probably where their technique came in - they used it to find the maximum possible size for this object, and since that size is so small, the only thing the object could possibly be is a black hole.

It measures the oscillation of hot gas piling up near the black hole as it sucks in matter, they told a meeting in Los Angeles of the American Astronomical Society High-Energy Astrophysics Division.

No, they didn't. I admit, I have no idea what they actually said, but I highly doubt they said anything about the black hole "sucking" - BLACK HOLES DON'T SUCK!!!! They don't. Sure, if something falls onto a black hole, it won't come out again, ever. But black holes don't actively suck material into them. The force of gravity works just the same near a black hole as it would near a star of the same mass.

A collapsing star that was much smaller than J1650 would likely form a neutron star and not a black hole, the researchers said.

I have two problems with this sentence. First, the word "smaller" is ambiguous. Do they mean a star with a smaller mass, or a star with a smaller size? A star with a smaller size doesn't make sense - such stars do not exist! So I must assume that they meant a star with a smaller mass. That poses a problem, as well. It has been well established that any star that starts with a mass up to 8 or 10 times the mass of our Sun will end it's life as a white dwarf. Only stars more massive than that will eventually become either a neutron star or a black hole. Of course, they are talking about a collapsing star, here, by which I assume they mean the core of the star that is left over after a massive star has gone supernova. Such a remnant needs to be about 3 times the mass of our Sun to become a black hole, otherwise it will become a neutron star.

See any more problems with the article? Let me know!

Cloud Watching on Mars

The Mars rover Opportunity looked skyward recently, and caught images of cirrus clouds passing overhead. See the animation at the Planetary Society Weblog.

Pretty Spiral Galaxy

If you don't check out the Astronomy Picture of the Day, you really should! Today's picture is very pretty. Go see it!

Most Distant Object Ever Visible to the Naked Eye

This is technically old news, but the Astronomy Picture of the Day today featured the gamma ray burst from a few weeks ago - they have a nice, concise description. Essentially it was an explosion that occurred half-way across the universe, but was actually visible to the naked eye! The picture might not be the prettiest you can find in astronomy, but the idea of just how bright this thing was, how much energy it had in order for its light to be visible 7.5 billion light-years away - it's mind-numbing! If this doesn't sound amazing to you, you must be missing something.

Paper Airplanes in Space

Some scientists in Japan want to make paper airplanes (origami planes, to be precise) and launch them from space, and see what happens as they come back to Earth. I'm not sure what to make of this... On the one hand it sounds neat - these scientists are pretty confident that, because of their small size, they won't burn up in the atmosphere, and that information learned from their "flight" might help design new spacecraft. On the other hand, paper airplanes are small, and therefore will be nearly impossible to track on their way to Earth, and will be very hard to find once they land. There's also something...weird, I guess, about research on paper airplanes getting $300,000 worth of research funding per year. There's actually a lot of complex testing that has been done and can still be done with the airplanes, so it actually does make sense, but it still just sounds weird. Read the article and see for yourself!

Cassini Finds Enceladus Tastes Like a Comet

Yup - that's a weird title! I can't take credit for it, I stole it from this article from the Planetary Society. It's a pretty long and involved article, though (I haven't even read the whole thing!), so you might prefer going to the Bad Astronomy Blog for a nice summary. Here's a brief synopsis: A few years ago the Cassini spacecraft discovered that Enceladus, a moon of Saturn, has plumes of water from geysers on its icy surface. That in and of itself is pretty cool. Earlier this month, Cassini flew right through a plume! Not only did they take pictures, but other equipment on board the spacecraft was able to, essentially, taste the particles being spewed out from the interior of Enceladus. Cassini detected organic (carbon-based) molecules in the water. This is pretty cool - the plumes indicate that there is liquid water underneath Enceladus's icy exterior, and organic molecules are the building blocks of life as we know it! Now, we don't know if there is actually any life in Enceladus, but the possibility sure is tantalizing!

An Actual Planet In The Making?

Planets around other stars are thought to be quite common. We've found well over 200 extra-solar planets (exoplanets) so far, and our planet-hunting technology is really still in its infancy. We've also seen many protoplanetary disks (aka proplyds, aka debris disks, aka circumstellar disks) around young stars - dense areas of dust and gas around a young star, where we expect planets to form in the future. Now, scientists believe they may have found a planet in the process of formation! They can't be sure as of yet, and it might be a brown dwarf instead (a brown dwarf is something that is not massive enough to be a real star, but too massive to be considered a planet). They see a gap in the protoplanetary disk (that marks the orbit of the nascent world, where it has swept up debris in its path), and they see a bright spot within that gap - this might be the object itself, or it could be the light given off by dust as it falls onto the object.

What Killed the Dinosaurs?

We know for a fact that a large piece of space junk crashed into Earth 65 million years ago. We also know for a fact that the dinosaurs died out 65 million years ago. So did that impact alone kill off the dinosaurs? That, we don't know. There was also more volcanic activity around that time, and this article supposes that the additional poisonous gases added to the atmosphere might have hastened the demise of the dinosaurs.

More Evidence of Past Martian Water

I'd say that scientists are about 98% certain that Mars once had abundant liquid water on its surface, and we're finding more and more evidence of this all the time. The most recent evidence is salt deposits, similar to the salt flats on Earth in places like the western US. Of course the reason we are so interested in (past) liquid water on the surface of Mars is because here on Earth, everywhere there is liquid water there is life - we hope the same may be true for other worlds, as well. These salt deposits might be a place to hunt for fossilized evidence of Martian life.

Deep Sea Pressures

What happens to a Styrofoam cup if you exert a pressure on it equal to almost 400 times atmospheric pressure? It shrinks!


Apparently scientists who study the depths of the ocean have been doing such "experiments" for decades - it just goes to show that scientists like to play, too! They've taken all sorts of things under the sea to see what happens to them under the pressure, and to discover what objects can actually survive such large pressures. What do you think would happen to a raw egg at the bottom of the ocean? Read the article to find out!

Breathtaking Milky Way

Wow, talk about an observing log! Astronomer Tyler Nordgren is on a quest to visit 12 national parks in one year, exploring the connections between the parks and the wonders of the night sky. His description of seeing the Milky Way from Big Bend National Park in Texas is simply breathtaking. It definitely makes me wish I had easy access to truly dark skies!

About This Blog

Hi! I've created this blog because I often find interesting things online that relate to the classes that I teach (physics, physical science, and astronomy), that I think my students might be interested in. For the most part, I'll be posting links to the things that I find along with a very brief summary - my intent is not to give all the information in my post, but to encourage the reader to click on the link for the fully story.