So lots of stuff from around the web:

1) GLAST launched! Yay!

2) Phoenix’s oven is ready to bake!

3) My good friend and great skeptic Richard Saunders is on an Australian TV show which is bound to be a big hit. Also, congrats to Karen Stollznow for becoming chief at The Skeptic, the magazine of The Australian Skeptics.

4) Objects like Pluto will now be called plutoids. I’m wondering how much more ridiculous this situation can get. Astroprof has more.

5) My friend (and hawt skepchick) Iszi has a podcast with Simon Dunn where they discuss the Sunday inserts in newspapers (it’s OK, they’re comedians). In their second episode, they talk skepticism and Iszi says I am very huggable (this happens about 16:50 into the ‘cast). I feel that this hasn’t been confirmed to a certain enough degree, and am volunteering to do more research with her as necessary. If you like their podcast, they have a Facebook group for it.

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.

Note: There is a special note to teachers at the bottom of this post. If you’re a teacher, please be sure to check it out!

My friend Tina is a teacher at the Saegert Sixth Grade Center in Austin, Texas. She asked her sixth grade students to send me questions they had about astronomy, and I answer them on camera. There were so many I had to split this into five parts! I’ll be posting one part every day, first thing in the morning. To catch you up, check out Part 1, Part 2, and Part 3. Below is Part 4.

The questions asked in Part 4 are:

1) Is there another planet past Pluto or inside Mercury’s orbit?

2) Why can’t we live without the Sun?

3) How do stars form?

4) Have the constellations changed?

5) Why is space black? Why doesn’t the Sun light it up?

6) Do galaxies move around in space and do they collide?

7) What is the biggest galaxy?

SPECIAL NOTE TO TEACHERS: Many schools block access to YouTube. There is another video hosting platform called TeacherTube, which is designed to be used in schools. I’ve uploaded this video (Part 4) to my channel there, where you can access it in your school (note: the video is in higher-resolution on YouTube). If you do, please let me know! I’d love to know what the students thought of the video — warts and all.

Note: There is a special note to teachers at the bottom of this post. If you’re a teacher, please be sure to check it out!

My friend Tina is a teacher at the Saegert Sixth Grade Center in Austin, Texas. She asked her sixth grade students to send me questions they had about astronomy, and I answer them on camera. There were so many I had to split this into five parts! Here’s Part 1.

The questions in this part are:

1) Why are you called the Bad Astronomer?

2) Have you ever been to space?

3) Do you think aliens are real?

4) If you were a scientist, what would you do?

5) Is there life on other planets?

6) Will humans ever live on the Moon or Mars?

7) What’s your favorite planet?

8) Pluto: planet or not?

There are 4 more parts to this video, and I’ll link to them as I put them up. Maybe one per day, first thing? We’ll see.

SPECIAL NOTE TO TEACHERS: Many schools block access to YouTube. There is another video hosting platform called TeacherTube, which is designed to be used in schools. I’ve uploaded this video to my channel there, where you can access it in your school (note: the video is in higher-resolution on YouTube). If you do, please let me know! I’d love to know what the students thought of the video — warts and all.

Could there be another planet lurking in the dark, frigid outskirts of the solar system?

This isn’t as silly as it seems at first. No, I’m not talking Nibiru or any of that other nonsense (and it is nonsense), I’m talking about an actual planet, Earth-sized or so, that could be orbiting the Sun well beyond Pluto Neptune.

Why would we think there might be one out there?

We see some stars in the midst of forming planets. The stars are surrounded by thick disks of material, and in some we can actually see gaps in the disk, dark rings like the gaps in Saturn’s rings, that we think are due to forming planets gobbling up material in the ring. You’d think the disk would fade away with distance form the star, like our air gets thinner with altitude. But some disks appear to have sharp outer edges. This can be caused by a planet orbiting outside the disk; its gravity sweeps up the material and over time cleans up everything farther out. In one disk, this sharp boundary indicates a planet 200 AU out (an AU is the distance of the Earth to the Sun, about 150 million kilometers or 93 million miles).

Neptune orbits at 30 AU from the Sun, so 200 AU is a long way out. Could a planet like that have formed in our solar system? Maybe. Thing is, while our proto-planetary disk has been gone for billions of years, we do have lots of objects out past Neptune: the Trans-Neptunian Objects (they have lots of names, including Kuiper Belt Objects). These are basically giant balls of ice, some hundreds of miles across. As a group they form a puffy disk of objects stretching from Neptune’s orbit outward… but they seem to abruptly stop past about 50 AU out from the Sun. That’s called the Kuiper Cliff, the cause of which is unknown. Incidentally, it’s not because they’re too faint to see (that is, they’re there but we can’t spot them); at that distance we should have spotted lots of them by now.

Not only that, but a lot of these objects have orbits that are tilted more and are more elliptical than you’d expect if they just formed a long time ago and were left alone. Theyir orbits don’t bring them in very close — they tend to stay outside of Neptune’s orbit — but again, this is something that needs to be explained.

Could it be that there is another massive planet orbiting the Sun, way out there, which has swept up the objects gravitationally, creating the Kuiper Cliff and tossing the iceballs into tilted, oval orbits?

A newly released paper shows that may very well be the case. A team of scientists ran a whole mess of simulations, and found that a small planet (in this case, around half the size of the Earth) could have formed inside Neptune’s orbit (where there was plenty of material in the early solar system), gotten tossed into a bigger orbit by Neptune, and then knocked around the orbits of the iceballs, distorting their orbits and creating the Kuiper Cliff.

This idea is not new, but this new research is a provocative indicator of such a planet’s likelihood of existence. I’m not saying it’s out there, but it’s worth looking for. In fact, I’ve been saying that since about 1998 or so, when I worked on Hubble and was involved with a project that found a truncated disk around another star. I even worked with another astronomer on the team to investigate whether the robotic telescopes used to look for Near Earth Asteroids could spot such a planet.

It’s not all that easy. It wouldn’t be too faint to see, necessarily, but it’s a big sky. At that distance, the planet would move slowly, and the orbital motion would be hard to distinguish given the procedures used by NEA searches. We tried to convince some of them to modify their software to look for Planet X (yes, why not, though now it would be Planet IX), but we were met with mixed success. The fact that no one has discovered this planet shows you that this is still hard to do.

But maybe, just maybe, with this new research we’ll get people looking more seriously. It’s amazing to me that we can understand so much about galaxies and hugely distant objects, but find that there may be surprises waiting for us in our own back yard.

First, I will make a caveat. Then, I will froth. Then, I will find the silver lining which makes this all better.

Caveat:

This is a delicate situation here. I love kids, and I love kids who love astronomy. I want to foster that love, and turn it into a lifelong interest in the sky, in astronomy, and in science.

Froth:

So having said that, what the heck was National Geographic thinking?

They held a contest for kids to come up with a mnemonic, a memory-aid device, to help them remember the order of the planets. Like, My Very Excellent Mother Just Served Us Nine Pizzas, which is the one I heard when I was younger.

I’m all for this. That’s a great idea. Except… in the rules it says this (emphasis mine):

Compose a mnemonic (memory trick) using the first letter of each of the planets in order from the Sun (Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Eris) as the first letter in a word. The words must make a fun and memorable English sentence (Example: My Very Excellent Mother Can Jump Slowly Under Nelly’s Plastic Elephant.)

Um, NatGeo? I hate to break it to you, but our solar system, officially, has eight planets. Pluto was kicked out years ago. If you want to be a Luddite and still accept Pluto as a planet, that’s fine, but really, Ceres and Eris too?

Nope.

Eris is an object similar to Pluto, but slightly bigger and more massive, well out past Neptune’s orbit (objects there are usually called Kuiper Belt Objects or KBOs). While it fits some of the new definitions of a planet, it doesn’t clear out its neighborhood of smaller objects (it’s too small, and the space it occupies out in the hinterlands of the solar system are too voluminous), and that’s one of the rules planets follow.

Same with Ceres, the largest asteroid. With thousands, millions, of asteroids in the same region of space, Ceres doesn’t hack it either. Besides, all three objects (Ceres, Eris, and Pluto) are smaller than our own Moon. If you include those three, there will be dozens more, hundreds more, you have to include as well. You might even have to include Pluto’s moon Charon (note; some of the things I said in that post were superseded by later rules imposed by astronomers on the definition of a planet).

So in the end, NatGeo would have done a lot better to leave Ceres and Eris off — they’re just not planets by anyone’s definition — and to be consistent they should have left Pluto off as well.

Silver lining:

Having said all that, I want to heap praise on the ten-year-old girl won the contest. The phrase she came up with is excellent:

It’s cute and it’s memorable (and it certainly follows the rules of the contest).

And in reality, what is very cool about this is we now have a little girl out there in Montana who not only knows the order of the planets, but she also knows a little something about asteroids and KBOs, too. How many ten-year-olds can say that? And I wonder, what’s in her future? Maybe eventually she’ll take an interest in the planet-naming controversy and help settle it. Maybe she’ll grow up to be an astronomer who discovers Earth-like planets orbiting other stars.

Where will her interests lead? For now at least, they’ve taken her billions of kilometers to the edge of the solar system, and for that, I am glad, and I congratulate National Geographic on holding the contest and doing something terribly, terribly important: igniting a spark for science.

Tip o’ the Whipple Shield to BABloggees John Phillips, Jeromy Labit, and Richard Velez for emailing me about this!

There are more misconceptions about black holes than probably any other area of astronomy (though I bet cosmology would give BHs a run for their money). A lot of TV shows and movies have exacerbated this, but now a toy enters the ring. Fischer-Price has created a series of action figures (or, as I like to call them, dolls) called Planet Heroes. And what are heroes without a nemesis? So they have introduced Professor Darkness (not to be confused with Captain Harkness or Butters’ alter ego).

For some reason, they have associated Prof. Darkness with black holes, as you can see from the package:

Sure, you may ask, how hard is it to make fun of a product with the tag line, "With his corrupt little minions and negatronic cloud, he has vowed to destroy the solar system!"? Well first of all, I was considering this very line as the motto for my website, but then I realized that

1) my minions aren’t (necessarily) corrupt, and

2) "negatronic" isn’t a word. But it should be.

Also, I’ll note that they have a hole in the plastic urging tots to stick their finger in it. Need I say it? It’s a black hole! Don’t put your finger on it!

Anyway, I applaud Fisher-Price for at least trying to get their description of black holes right, I suppose, but they missed the mark a bit. Well, more than a bit.

The description (seen at the bottom of the picture) has two lines:

A black hole happens when a giant star explodes and collapses.

Can be found anywhere in the solar system.

The first part is close, but unfortunately makes things worse. A black hole can form when the core of a very massive star collapses. Complicated physics ensue (as many details as you could possibly want will be forthcoming in my book), and the utter layers of the star explode outward while the inner core collapses inward. If the core is massive enough, a black hole will result.

Many people get confused about how a star which explodes outwards can form a black hole. But only the outer layers of the star explode; the inner part is what forms the black hole. So Fisher-Price got close, but wound up only confusing things more.

The second one is a bit scary. Black holes are in the solar system! Run for your lives!

First off, I think FP made the all-too-common mistake of confusing the solar system with the Milky Way galaxy. A lot of folks do this (heck, Joss Whedon did in Firefly at least once), but it still makes things difficult for people to understand the scale of space. Our solar system is huge on human terms — it takes our probes decades to get to Pluto, for example — but it is crushed into insignificance by the size of the galaxy. The Milky Way is 100,000 light years across, while our solar system is charitably a light week across. That makes the galaxy five million times bigger than the solar system.

And that’s only diameter. The galaxy has depth, too. Its volumes is approximately… let’s see… carry the three… a bajillion times that of the solar system. It’s no contest.

The galaxy is filled with black holes; no doubt millions of them wander the deep black. But even so, the nearest is probably many dozens or even hundreds of light years away.

And if one were in our solar system, we’d know it. Things would be bad. Again, I give lots of nightmarish details in my book (due this fall from Viking! Order two!), but in general the planets would be out of place, comets would be screaming down from the outer reaches of the system, gamma and X-rays would be flooding out… we’d know. It’s hard to hide a black hole.

So let me wrap up by saying black holes are cool, but grossly misunderstood. Fisher-Price is also cool, and attacking it, even gently and somewhat tongue-in-cheek, may be silly. But I love taking the opportunity of someone else’s error to actually do some real astronomy education. If you want to buy those dolls action figures for someone you know, why, go ahead! But point the kid to a reputable astronomy site, too. After they’re done playing some fantasy, show them how cool the real Universe is too.

Tip o’ the ergosphere to Stanley Wen for pointing this out to me on Facebook.