back to article NASA probes seek remnants of lost 'Theia' planet

A pair of NASA "space weather" monitoring spacecraft are having something of a change of pace, as they search for evidence of a long-lost world which may once have crashed into the Earth, and so formed the Moon. The two probes in question are those of the space agency's Solar Terrestrial Relations Observatory (STEREO) …


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  1. Elmer Phud

    Don't go there!

    Isn't that where the aliens are hanging around, monitoring everything?

    Are we about to wake up the Thetans?

  2. Anonymous Coward
    Anonymous Coward


    I suppose calling this lost planet "Mondas" would either not go over well or simply wouldn't occur to Americans in the first place...

  3. Mike Richards

    Carl Sagan walks amongst us

    'Boffins think the planet-smash theory of lunar formation could explain why the Moon has such a relatively unimpressive iron core, being made up mostly of melted crusty bits smashed off in the possible Earth/Theia pileup and then blobbed together.'

    Brilliant, it's the grasp of the precise language of planetary geology that makes it so authoritative. Please make sure all future stories include the word 'billions'.

    It's worth adding, had the Moon had a normal origin, it's relatively small size would have precluded it ever getting hot enough for an iron core to differentiate, so you still wouldn't expect things like a planetary magnetic field or active vulcanism.

    The collision theory is better supported by doing high precision work on lunar rocks ('hittin' it wiv an 'ammer' in geological parlance); they're very rich in refractory minerals and depleted in volatiles such as carbon, hydrogen, nitrogen and the noble gases.

    Thumb Up

    Superb animation!

    Who produced the animation? Is it based on real data or only illustrative?

  5. Anonymous Coward
    Anonymous Coward


    Sounds a lot like the Sumerian tale of Tiamat coliding with a Nibrun moon, creating earth as we know it today, the moon and the asteroid belt.

  6. Anonymous Coward
    Anonymous Coward

    There better not be too many big bits of junk up there

    or throwing sophisticated probes through them may prove to be rather expensive and messy.

    Also, Solar Terrestrial Relations sounds a bit rude.

  7. Anonymous Coward
    Anonymous Coward

    I hate to pittle on your parade.

    But if the pope is right, and I'm sure Archbishop Vincent Nichols can confirm that the pope is never wrong, then the earth, moon and everything else was created by a fairy with a beard.

    Not just that, but I should point out the facts, with which I suspect our new catholic representative has probably terrified many a child in his time into coming round to his way of thinking, YOU'RE GOING TO BURN IN HELL FOR ETERNITY if you don't believe this, and give the catholic church all your money.

    I'm just telling you all now, so that you don't get as far as dying without having admonished this "Science" from your heretic minds.

    Oh! One more thing. The Earth is flat, ok.

  8. Anonymous Coward

    Tiamat story fo the Sumarians

    Seems most astronomy is finally putting ancient knowledge into present fact, after centuries of poo-pooing it as myth. Their myths helped with the search for Neptune, Uranus, and Pluto. Due to anomalies in orbits of planets that could only be explained by something larger further out there. Since each further out planet shows similar anomalies, the so called Planet X has yet to be discovered.

    Not to mention the moon is barely spherical, and is moving further from the earth, making one likely to assume the earth and moon shared the same space at some point. With the less than fact accretion theory that is getting less and less believable with the further accumulation of observations in our solar system, more evidence points to there being a lot of chaos in the formation of the solar system, and not that the planets formed together in the same relative positions we see them today.

    But what do I know? We're supposed to believe all the scientists that will say what they need to in order to make their money. The current new knowledge is obviously a ploy by those who can't get the cash to make themselves seem important... obviously.

  9. Frank


    Thank you for the fascinating animation, I had hours of fun watching it. Can anyone tell me why there is a clustering of asteroids (at L3 of Jupiter?) at the bottom of the picture? A relatively small number of asteroids slow down and do a little loopback there. Is it the effects of Saturn, not visible on the image, or maybe it's a problem with Uranus?

    Furthermore, (I really did pay attention), I can appreciate why the Lagrange point at the upper left of the picture collects asteroids, since going past Jupiter would slow an asteroid down as it got pulled back under the influence of Jupiter's gravity; but I can't figure out why the asteroids slow down and congregate at the upper right Lagrange point.

  10. Tom Cooke

    When Worlds Collide, mythology

    Oo! Oo! Can anyone say "Velikovsky"?

  11. Anonymous Coward
    Thumb Up

    "solar-corona probing kit"

    That bit made me thirsty and excited for some reason!

  12. Telecide
    Paris Hilton


    can someone explain why, in the animation, the earth is tanking it around the sun while Jupiter is not orbiting at all?? Is there something about the gas giant that I missed??

  13. TeeCee Gold badge

    I know just how they feel.

    "Taking the time to observe L4 and L5 is kind of cool because it's free,"

    A sort of outer space version of the Angel of the North then. Oodles of people have seen it, but only while whizzing past on the A1.....

  14. Frank

    @Telecide re.Confused

    The Lagrangian points of Jupiter (or more accurately the Sun-Jupiter pair) are considered in a rotating reference frame, hence the 'point of view' is rotated continuously so that Jupiter appears to be stationary. I learned this by reading about it in Wikipedia ) - but I'm sure there will be a deeper treatment somewhere else if you're interested.

  15. 4a$$Monkey

    You are all wrong

    It is well known that the moon is made of cheese. I would have thought you would know that!

  16. Ken Hagan Gold badge

    Re: confused

    The animation is in the frame of reference of Jupiter, so in the (more conventional) frame of reference of the Sun the whole diagram is rotating slowly.

  17. Nigel


    It's showing the situation relative to Jupiter, i.e. in a frame of reference that is rotating around the Sun at the same speed as Jupiter. If it was shown in a non-rotating frame of reference you'd get a much less good idea of what was actually going on (and you would get dizzy trying to work it out).

  18. Lukin Brewer

    There is no tenth planet.

    ...or ninth now that Pluto has been demoted. Yes, Uranus was discovered from the perturbations it caused in Saturn's orbit, and Neptune was discovered from the perturbations it caused in Uranus's orbit. Then Pluto was discovered, apparently, from the perturbations in Neptune's orbit. But Pluto appeared to be too small, and so the hunt for a tenth planet commenced. All sorts of possible theories and configurations were proposed to explain the existing data. The expanding branch of chaos theory added to the mess: relatively small changes or inaccuracies in initial values could change the behaviour of the model completely, and they only had estimates for the masses of the planets, based on observational data. When the Voyager missions concluded, it gave them, among many other things, accurate mass data for the outer planets. They plugged in the new data and ran the simulation again. Result: no anomalies - all the observed perturbations were accounted for. Unfortunately, "Tenth Planet Ruled Out" did not make a good headline outside the scientific press, and so it isn't common knowledge. The only major worry from a scientific viewpoint was that it might then make the discovery of Pluto, in the location predicted by the erroneous model, a wild fluke. However, observational data from the new Hubble Telescope showed that Gerard Kuiper's theoretical belt of planetoids and cometary nuclei was actually there beyond the orbit of Neptune, and some of the bodies were actually planet-sized. Pluto just happened to be the one in the place where they were looking.

  19. Nigel

    @anonymous coward

    The moon would be slowly moving away from the earth regardless of how it got there in the first place. The cause is tidal drag. The rotating earth is dragging on the moon, and as the Earth's own spin is transferred to the Earth-Moon system, the orbit has to enlarge. It would end when the earth has one face permanently pointed at the moon, like the moon already has one face pointed permanently at the earth. "Would", because the Sun will go nova first, a few billion years from today. Slightly before that, it will have eaten the Earth-Moon system.

  20. Dr Patrick J R Harkin


    Well remembered - you must be as grey as I am! Let's start a petition at the No. 10 website calling for all UK-funded scientists (i.e. both of them) to use the name "Mondas".

  21. Adam Foxton

    @Sumerian stories / ancient knowledge AC

    Well that's all they were- stories. There was no available evidence for or against them.

    The thing with Science is that it takes the mysticism out of things and replaces it with fact, overlaid with a wonder about that fact and the incredibly complex universe that we live in. And from that solid base it lets us drill down further, finding out the "why" of events.

    The reason that these more ancient stories make more sense than the more modern ones is that the Sumerian civilisation ended over 4,000 years ago. So any myth and legend was nicely preserved in it's original state- not politicised or subjected to the huge cultural influences that worldwide religions have. Originally these things would have been either derived from observations or from stories told by others (*clicks fingers, points* Aliens!).

    Yes, more attention should be paid to these older myths- but they should probably stick with the "spooky co-incidence" type stories- things like the Deluge that are mentioned over vast areas of the world. Things that are likely to have actual evidence behind them.

  22. Anonymous Coward

    Nice animation, but...

    ...I was wondering how long it would take anybody, including el Reg's staff, to google for 'jupiter l4 l5', find the site that snippet of news (including the image) is originating from, follow from there to the site of the author of the animation and discover right there at the top of the site the following two sentences:

    "Copyright (C) 2003-2009 by Aldo Vitagliano

    Copyright Information: Text and images in this site may be freely reproduced, provided credit is given to the author."

    Tux 'cos he might be a bit dissapointed. AC 'cos I should be working right now.

  23. Anonymous Coward
    Anonymous Coward

    Still got it wrong.

    James P. Hogan documented that it was the aliens with the minature black hole drives some years ago. When will these people learn to keep up on their reading.

  24. James Hughes

    Earth Fast, Jupiter slow

    The earth seems to be moving very fast, because, er, relative to Jupiter, it is fast. Earth orbital period is 365 days or thereabouts, Jupiter is 4331 ish days. That and the fact that the frame of reference is Sun-Jupiter, explains the difference.

  25. Anonymous Coward
    Thumb Down

    @ Tiamat story to the 'Sumarians' AC

    Google "Dunning-Kruger effect".

  26. Anonymous Coward
    Anonymous Coward


    "...because the Sun will go nova first, a few billion years from today. Slightly before that, it will have eaten the Earth-Moon system."

    No it won't go nova, it will expand to become a red giant. It can't go nova unless it's already become a white dwarf and a sufficient mass of hydrogen has accumulated on its surface to trigger fusion in the hydrogen layer. But yeah, Earth and the Moon will be toast either way.

  27. SRD-BCCM

    Third planet

    The origin of the moon seems to have crept into the article. The chemical composition of the Moon is so different even if it evolved by differentiation and it did it is impossible to say that the Moon is a part broken away for the original Earth. There is no chemical similarity. As a matter of fact, lunar composition on the whole more closely resembles the Earth's upper mantle in terms of crystalline state with no water of course.

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