Blogs / Bad Astronomy

I am never ceased to be amazed at the garbage spewed by quacks the "diet supplement" industry.

The latest? Something called "Tunguska Blast!" What is it? Why, according to the website, it’s:

… a powerful dietary supplement originating from the miracle of 1908 in the Tunguska region of Russia.

In 1908, a chunk of rock 10-20 meters across exploded high in the atmosphere over a remote region of Russia, flattening trees and causing an explosion that was literally felt around the world. Called the Tunguska event (after a nearby river), it has caused endless research in the scientific community and endless nonsense in the antiscientific one.

What does this have to do with an energy drink? Well…

From among thousands of herbs, roots, and fruits reborn from the ashes of the mysterious Tunguska Event, scientists identified the ten most concentrated with therapeutic properties and natural nutritional benefits.

Of course! After all, nothing says healing like the explosive equivalent of 5 million tons of TNT!

The ingredients of the supplement are the usual mishmash of plants generally blended into such things. They may indeed be therapeutic — there are some that have antioxidants, for example, and one has flavonoids (which I suspect is something the writers for The Simpsons made up just so Professor Frink could say it) — but as always, it pays to dig into the site, where you find this bit:

That says: "The statements on this product have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any diseases."

In other words, this product may not do anything its makers claim it does.

I am not saying this product does nothing, nor am I saying it either helps or hurts you — though I must note that many of these dietary supplements, even most of them, have not been tested at all in conjunction with the use of other supplements, which means you can sometimes get synergistic effects which can be harmful, even fatal — but what I am saying is that tying this product to the Tunguska blast is remarkably silly, even in a market known for an unlimited supply of utter nonsense.

I suspect most anyone who reads this site would know better than to buy stuff like this. But even I have to admit: the bottle is cool.

Tip o’ the homeopathic qi-aligned feng-shui induced chiropractic tin foil beanie to ToSeek, who is apparently everywhere.

Today’s first American Astronomical Press conference is on weird binary stars, and will star at 9:40. I’ve embedded the video below. If you want to participate in the chat room, go to the UStream channel.

TV Show hosted by Ustream

I mentioned earlier that all big galaxies have big black holes in their hearts. I also mentioned that the size of the black hole is related to various features of the galaxies, but that might be a little weird because, after all, galaxies don’t live in a vacuum^*. There are other galaxies out there, and they sometimes collide, forming bigger galaxies. So why should there still be a relationship between the black hole and the galaxy it sits in?

Well, the idea is that when two galaxies collide and merge, so do their black holes. Complicated physical processes tend to favor the two black holes getting ever closer, until they eat each other and become one somewhat fatter black hole. At the same time, the galaxy formed by the merger around the two black holes also grows.

That’s the idea, at least. But there’s a way to see if that’s what really happens.

For example, when two galaxies collide and merge, their gas clouds collide. This can collapse them, forming stars. But since the event happens over a short period of time — compared to the age of the galaxies, at least — it’s called a star burst, or a burst of star formation. Massive, luminous stars form this way and stay bright for a few hundred million years.

Also, at the same time, it’s expected that a vast amount of gas will fall to the center of the new galaxy. As this junk falls into the black hole, it forms a flat disk which gets incredibly hot and bright. The inner part of the disk can outshine the entire rest of the galaxy combined. This kind of galaxy is called a quasar.

So if this idea is right, you might expect to see some galaxies that are quasars, and show signs of having had a star burst a few hundred million years in the past. Not only that, you’d expect them to look a little funny, distorted and goofy-shaped after having suffered such a cosmic collision.

Enter Mike Brotherton, astronomer, science fiction writer, blogger and, may I add, BABloggee. He and his team figured that they could use Hubble to look at a bunch of these galaxies and see what’s what. They went through a sky survey that had 15,000 quasars (!) and culled them down to 600 that looked promising. From those they picked the best 29, and when they got the Hubble observations what they found was pretty convincing…

Those are three of the 29. Look at them! Weird, twisted, distorted; just as expected. In fact, all 29 were pretty weird (check ‘em out yourself). They all bear the scars of recent mergers, and support very strongly the idea that "post-starburst quasars" are the results of violent collisions between galaxies, and, furthermore, black holes and their galaxies grow together.

Take a close look at those images. Right now, even as you read this (assuming you’ve read this far), the Andromeda Galaxy is barreling toward us at more than 100 kilometers per second. In a billion years, plus or minus, we’ll plunge together in an event of epic violence. If there is any gas left in our two galaxies — I haven’t been able to confirm whether it would all be used up by then or not, but at least one paper I’ve read (and quoted in my book, Death from the Skies!, about this) said it’ll all be gone — then we too will become a starburst galaxy, and if any gas gets dumped into our merging black holes a vast amount of energy will pour out. It’s potentially enough to cause problems, should that energy be aimed our way.

However, we do still have quite a bit of time to work out any potential problems. I’m not too concerned about it. But what a view it’ll be…

More brown dwarf news came out of the last press conference: the masses of some of the lowest mass brown dwarfs have been found using the powerful Keck telescope in Hawaii. They did this by precisely measuring the orbits of binary brown dwarfs, and from the well-known equations of how bodies orbit one another the masses were found.

Images of the two brown dwarf binary systems from the Keck telescope. Credit: Michael Liu (IfA, U Hawaii) and Trent Dupuy and Michael Liu (IfA, U Hawaii), respectively.

Amazingly, one binary system (2MASS 1534-2952AB) appears to be comprised of two brown dwarfs each of which have only 3% the mass of the Sun! This makes them the lowest mass and coldest objects (outside of extrasolar planets orbiting other stars) for which a mass has been found. Another binary (HD 130948BC) was measured as well, and each star has a mass of 5.5% the mass of the Sun — and as you can see in the image above, this pair orbits a third star which is more like the Sun, which is why it appears so much brighter.

While this is pretty nifty in and of itself, it gets better when these masses are compared to the theoretical masses of the brown dwarfs derived from the equations expected to describe them, and then looking at the other characteristics of the failed stars. When that’s done, the first pair is cooler than expected, and the second pair warmer! That means the theories need to be tweaked a bit. It’s probably not anything hugely serious, but it’s interesting nonetheless.

Both binaries are about 50 light years from the Earth — if they were much farther away they’d be too hard to study, even with Keck — and in both pairs the stars are separated by about twice the Earth-Sun distance.

Note to my readers: if you like any of these news stories coming out of this meeting, then please feel free to click the yellow Digg button to help spread the word! Thanks.

News flash! The lowest mass planet yet found just so happens to orbit a very low mass star — so low mass, in fact, that it might not even really be a star.

Artist’s conception of the newly found system. Credit: NASA

OK, first, the planet. Called MOA-2007-BLG-192Lb — of course! — it has a mass of about three times the Earth, making it the lowest mass planet found so far. It orbits its parent star at about the same distance Venus orbits the Sun. However, that doesn’t make the planet terribly hot: the host star is itself may be a brown dwarf, in which case the planet may be as cold as Pluto!

The star is right on the borderline of what can be called star. By consensus, a star can maintain fusion in its core over long periods of time. Fusion is what powers the star, heating up the core and making the star shine. The Sun fuses hydrogen into helium (700 million tons every second!) which is what powers our star. But that’s maintained by the tremendous pressure at the Sun’s core. An object less than about 8% of the Sun’s mass won’t be able to squeeze hydrogen together hard enough to fuse it. In that case, it’s called a brown dwarf. It can stay warm for a few billion years just from the leftover heat of its formation, leaking out radiation slowly but never able to regenerate it.

The thing is, the exact mass of the newly found star is not known, so it may be just below or just above that limit. This makes a difference to the planet, certainly — its temperature depends directly on it! — but also on our theories. There are competing ideas of how brown dwarfs form, and being able to have a planet form nearby will certainly have people scratching their heads and trying to figure out how to manufacture a system like this.

There is a problem: the star (or whatever) and planet are 3000 light years away! They were not detected in the usual way by direct observation, but were found by gravitational lensing. The path a light ray takes bends when it passes a massive object. The gravity of the object can also amplify the light from stars behind it. In this case, both the planet and the dinky star were fund by this brightening of a background star. The amount of brightening can be used to determine the masses of the planet and the star, but not with perfect precision; hence the question on the stellar nature of the star. The planet’s mass is pretty secure, at least that it’s very low, only a few times that of the Earth.

In the end, we have at least one very cool thing about this announcement, and that’s the lowest mass planet yet found. At that mass, it’s almost certainly a rocky or icy body, and not a gas giant like Jupiter. And, if it does indeed orbit a brown dwarf, well, that’s pretty excellent too. But either way, say hello to our little friends.

Pamela and her minions — that includes me — will be streaming video of the press conferences here at the AAS live on the Astronomy Cast UStream channel. I’ve embedded the player below, and I’ll try to post this every day with a schedule so you know when to tune in (the next one is at 11:30 Central time, or 17:30 UT, and it’s on brown dwarfs and planets).

What this means is that you will get the news from the mouths of astronomers at the same time as the press and the rest of the world. So instead of reading my own interpretations of the news, you can read them and compare them to what you heard too.

Streaming Video by Ustream.TV

As usual, you can join the chat room… and if we see a good question, we’ll ask it!

The thing about black holes is, they’re black. That makes them hard to find, of course, but once you find one it’s also hard to get any information about it. The only way we can figure out anything about them is by looking at how they affect things around them: how stars orbit them, how material falls in and gives off light, and so on.

After observing many galaxies over many decades, it was found that every large galaxy has a supermassive black hole at its core, where supermassive means thousands, millions, or even billions of times the mass of the Sun. The way to weigh a black hole is to carefully measure the velocity of stars in orbit around them; the faster they move, the more massive the black hole. Thanks to Kepler, we can use those measurements to get a decent estimate of the central black hole mass.

But this can be hard to do, especially for distant galaxies. It takes long exposure times, intensive analysis, and generally quite a bit of work. But now astronomers have announced a very interesting discovery: spiral galaxies with more massive central black holes tend to have their arms more tightly wrapped. Galaxies with lower mass black holes seem to have more loosely wound spiral arms.

Why this would be is something of a mystery, and to be honest the discovery is not on absolutely firm ground. What they have uncovered is a correlation, not a rock solid cause-and-effect, but their data so far look pretty good. This idea pans out, that means that getting the mass of the central black hole in a spiral galaxy may be as easy as simply taking the galaxy’s snapshot and looking at the spiral arms. Incredibly, this means the central black hole’s mass can be determined for galaxies that are eight billion light years away!

The Andromeda (left) and Triangulum (right) galaxies. Andromeda has tight arms and a massive black hole, while Triangulum has loose arms and a lightweight black hole. Images courtesy T. Rector and B. Wolpa, NOAO/AURA/NSF, and T. Rector and M. Hanna/NRAO/AUI/NSF/NOAO/AURA, repsectively.

So, for example, the Andromeda galaxy, which has a very massive black hole in its heart — nearly 200 million times the mass of the Sun, or about 50 times the mass of the black hole in the center of our Milky Way — has its arms relatively tightly wound up. But the Triangulum galaxy, which has loose arms, has a low-mass black hole in its core, just a few thousand times the Sun’s mass.

The mass of the central black hole turns out to be pretty important in the life of the galaxy… though probably not why you’d think. Even the most massive black hole is only a tiny fraction of the total mass of the parent galaxy — far less than even 1%! But it turns out that the mass of the black hole seems to play an important role in how the galaxy itself forms. The black hole forms at roughly the same time as the galaxy itself. As the black hole gobbles down matter, it can get what is basically indigestion, eating material too quickly. This sets up a wind of matter that blows out from the black hole, and that in turn disturbs the gas in the galaxy. That gas is what forms stars, so the star formation history of the galaxy can be affected by its central black hole. This in turn can affect how mass gets distributed in the disk of the galaxy, and that’s — maybe — why the arm structure is affected by the black hole.

However, galaxy history is fraught with danger. Galaxies collide, or slide past each other and mess each other up. This also affects how the disk and arms behave, so obviously this situation gets complicated quickly. Worse, dark matter may play a role as well, but it’s not clear how that might work either. But if the result that black hole mass somehow correlates with the spiral arm shape is correct, that will give astronomers yet another handle on how galaxies interact with the monsters at their hearts.