
"The name of the planet is Theia," says Mike Kaiser, STEREO project scientist at the Goddard Space Flight Center.
The "Theia hypothesis" is a brainchild of Princeton theorists Edward Belbruno and Richard Gott. It starts with the popular Great Impact theory of the Moon's origin.
It's a good theory, but it leaves one awkward question unanswered: Where did the enormous protoplanet come from?
Belbruno and Gott believe it came from a Sun-Earth Lagrange point.
Sun-Earth Lagrange points. The STEREO probes are about to pass through L4 and L5. Solar observatories often park themselves at L1 while deep space observatories prefer L2.

It starts with the popular Great Impact theory of the Moon's origin.
A major clue to Nemesis's existence is a mysterious dwarf planet called Sedna that was spotted on an elongated 12,000-year-long orbit around the sun.
Mike Brown, who discovered Sedna in 2003, said: "Sedna is a very odd object – it shouldn't be there! It never comes anywhere close to any of the giant planets or the sun. It's way, way out there on this incredibly eccentric orbit.
The only way to get on an eccentric orbit is to have some giant body kick you – so what is out there?"
To avoid confusion with the Nemesis model, astrophysicists John Matese and Daniel Whitmire at the University of Louisiana at Lafayette dub their conjectured object "Tyche" — the good sister of the goddess Nemesis in Greek mythology, and a name proposed by scientists working on NASA's Wide-Field Infrared Survey Explorer (WISE) space telescope.
The researchers noted that most comets that fly into the inner solar system seem to come from the outer region of the Oort cloud. Their calculations suggest the gravitational influence of a planet one to four times the mass of Jupiter in this area might be responsible.
Two centuries of observations have indicated an anomaly that suggests the existence of Tyche, Matese said. "The probability that it could be caused by a statistical fluke has remained very small," he added.
The pull of Tyche might also explain why the dwarf planet Sedna has such an unusually elongated orbit, the researchers added.
If Tyche existed, it would probably be very cold, roughly minus 100 degrees F (-73 degrees C), they said, which could explain why it has escaped detection for so long — its coldness means that it would not radiate any heat scientists could easily spot, and its distance from any star means it would not reflect much light.
"Most planetary scientists would not be surprised if the largest undiscovered companion was Neptune-sized or smaller, but a Jupiter-mass object would be a surprise," Matese told SPACE.com. "If the conjecture is indeed true, the important implications would relate to how it got there — touching on the early solar environment — and how it might have affected the subsequent distributions of comets and, to a lesser extent, the known planets."
The fact of Tyche's existence is questionable, since the pattern seen in the outer Oort cloud is not seen in the inner Oort.
"Conventional wisdom says that the patterns should tend to correlate, and they don't," Matese said.
If the WISE team was lucky, it caught evidence for the Tyche solar companion twice before the space observatory's original mission ended in October. That could be enough to corroborate the object's existence within a few months as researchers analyze WISE's data.
The fact of Tyche's existence is questionable, since the pattern seen in the outer Oort cloud is not seen in the inner Oort.
Q: Why is the hypothesized object dubbed "Tyche," and why choose a Greek name when the names of other planets derive from Roman mythology?
A: In the 1980s, a different companion to the sun was hypothesized. That object, named for the Greek goddess "Nemesis," was proposed to explain periodic mass extinctions on the Earth.
Return to Electric Universe - Planetary Science
Users browsing this forum: No registered users and 1 guest