Expert: Courtney Seligman - 3/12/2010

Question
QUESTION: Hi Courtney, I've been reading recently about theories for the end of the world in 2012, and apparently there is this mysterious planet named "Plantet X (Nibiru)" that passes by the earth every few thousand years. Taking away all these end of the world sagas does this planet really exsist? As I've seen references from Nasa that there is a new planet out there with a very strange orbit. Is there concrete evidense of this new body that enters the solar system? And have you heard about this?

I've attached an image of the apparent orbit of planet X.

Thanks Courtney!!

Scott.

ANSWER: There is no planet X, in the sense discussed by those who believe in Nibiru. That is a fairy tale made up to sell fantasy-as-supposed-fact books (I think about 10 to 15 years ago), which has been perpetuated ever since.

Any reference by NASA to a planet X would either be a misguided effort to quash this nonsense (which is a waste of time, as such nonsense is like the Hydra -- cut off one head, and it grows two or three more), or an extension of 19th-century references to possible unknown outer planets as Planet X, to provide a name for discussion.

There certainly are objects well beyond the orbit of Pluto with interesting characteristics and orbits, but no object of significant size has an orbit like the one in the image you forwarded. Comets do have orbits that start far out, and come in as close as the outer atmosphere of the Sun; but so far, none of the larger objects detected beyond Pluto have orbits that come in even as close as Neptune. (Note added after original post: I looked up a couple of the sites where the picture you sent was posted. Absolutely nothing on either of them has any relationship to the truth. Even where real things, such as the South Pole Telescope, are referred to, their supposed purpose and discoveries are completely misrepresented. Without naming names, one of the sites is that of a deluded individual who accepts the other site's lies as gospel; while the other is obviously run for fraudulent commercial purposes. The former will presumably be relieved when the end of the world doesn't come; the latter will simply move on to another fraud.)

As far as 2012, part of that fairy tale has to do with misinterpretations of the purpose and use of the Mayan calendar, but much of it was deliberately invented by Sony to promote their movie of the same name.

I might note that there is a wide range of hucksters willing to bend the facts, or lack thereof, to support their fraudulent efforts. Even astronomers are not immune to the lure of easy money. For instance, The Jupiter Effect was a best-seller written by two would-be astronomers, based on research which had already been shown to be be fatally flawed. The publication of their stupidity-presented-as-godlike-revelation book made them pariahs in the astronomical community, but gave them the wealth they needed to laugh all the way to the bank.

---------- FOLLOW-UP ----------

QUESTION: Thanks Courtney. Yeah I bet when 2012 comes to an end the end of the world will happen in 2018 and then after that 2025 or something. Just like it was supposed to happen on Septemeber 9th 1999. However the mystery of these such things does capture my imagination abit. I thought how spooky this is, this strange planet eeriley entering the solar system that's going to cause the end of the world. I love astronomy though, and I have a head for facts; so I'm not going to completely lose myself over such claims.

I have another question. Are there any threats of comet or asteroid impacts within the next 50 years that you have heard of? Either ones that have the size that could destroy a city, or even ones that can cause total global damage?

Also what's worse? A comet or asteroid hitting the earth? I have heard comets usually travel at faster speeds making the energy they release greater, but asteroids are made of solid rock which would make them heavier, even though I can imagine a huge chunk of dirty solid ice to be a pretty tough cookie in itself!

ANSWER: There is nothing currently known (which, among other things, means large enough to notice) to have any significant chance of hitting the Earth during that time period. There are always one or two near-Earth-objects that have been so recently discovered that the uncertainty in their orbits gives them a 1 in 1,000 or 1 in 10,000 chance of hitting the Earth at some time, but the longer their motion is studied, and the more accurate calculations of their orbits become, the less chance there seems to be of their coming close enough to be of concern. Sooner or later something will hit us, but so far, we don't know what or when (just that it's a certainty, if you talk about time periods in the one to five million year range).

As you noted, asteroids and comets are both dangerous, though for different reasons. The greater density of asteroids means that a collision at a given velocity will be more energetic, but comets would tend to hit us at much higher speeds, because they move faster, and could be going in the opposite direction from our orbital motion, which would make their relative motion much faster. Also, the comets we can easily notice are substantially larger than the mostly smaller asteroids which have some chance of running into us, which would give them a substantial mass, despite their low density. So offhand, I'd expect a cometary impact to be more energetic, and therefore more destructive.

However, in the current era, it looks like the chances of an asteroid collision are substantially larger than those of a comet collision. About half the large impacts in the last 150 million years are thought to be due to fragments of an asteroid collision at that time, and at least some would be due to other asteroids. So although large cometary impacts could be disastrous (and quite possibly unavoidable, since most comets aren't discovered until they enter the inner solar system), they probably aren't as common as major asteroid impacts. (This does lead, however, to the uncomfortable possibility that even if we catalog every single NEO, it won't reduce the chances of an unexpected and catastrophic collision by more than 70 or 80%. But since the time between such collisions is in the million plus year range, it's more likely that the human race will expire of some self-induced catastrophe, than from any celestial catastrophe.)

---------- FOLLOW-UP ----------

QUESTION: Thanks for the fantastic info! Oh my god!! A huge comet going the opposite direction from the earth's orbital motion and hitting sounds absolutely disaterous. Am I correct in saying the earth is moving at a speed of 65,000mph as it orbits the sun? I heard this somewhere once. And can a comet travel anywhere between 15,000 and 50,000mph? The crater would be huge!!! Courtney, how big do you think a comet would have to be to hit the earth and knock it off it's orbit or axis, coming in the opposite direction from the earth's orbital motion if moving at the speeds I just described? Also, I don't know if this is your field, but how high would the mega tsunami be if a 1 mile asteroid hit the atlantic ocean?

Thanks again!!

Answer
The Earth does move around 65 thousand miles per hour. A comet could move through our part of the solar system at about 90 thousand miles per hour. So the relative speed of an impact could be more than 150 thousand miles per hour, under "ideal" conditions. And we do run into meteoroids moving like that, on occasion (that's why meteors seen after midnight are brighter, on the average, than ones seen before midnight; the ones seen beforehand are mostly catching up with us from behind, while the ones seen afterwards could be moving in the opposite direction from us). There would also be a small boost in speed due to our gravity, but for objects moving at such a speed, that effect would be relatively small.

Although the local effects of such a collision might be spectacular, changing the orbit of the Earth is no easy task. Even if something as big as the Moon ran into us at such a speed, it would affect our overall motion by only a percent or two, which isn't much more than the width of a line used to show our orbit in a diagram. So even an impact which blew much of the Earth's crust into space (mostly to fall back on the surface, afterwards) wouldn't significantly change our orbit, and comets are far too small for that sort of thing. The biggest ones we've ever seen were only a few tens of miles in diameter, not thousands of miles across.

That doesn't mean that the "local" effects couldn't be immense. I don't know how big a tidal wave would be created by a mile-wide asteroid, but I do know that such an object would create a crater 20 to 30 miles in diameter if it struck land. A considerably larger object would produce far larger effects. The approximately five mile wide object which hit the Earth 65 million years ago created a crater about 150 miles across, and a tidal wave which swept right over the top of all the Caribbean islands, including Cuba and Haiti, and up what is now the Mississippi river valley as far as Kansas and Nebraska. The effects of a one mile wide asteroid impactor would be a hundred times smaller, but occur on a far more frequent basis, since smaller asteroids are far more common than big ones.