Earth must have felt pretty inadequate a week or two ago when astronomers announced that distant Pluto has yet another moon. Pluto! Recently demoted to a dwarf planet! And yet it boosted its satellite total to four, while we remain forever stuck at one. True, Earth is ahead of Mercury and Venus, which have no moons at all. But Mars, which is significantly smaller than Earth, has two; and don’t even mention Jupiter, with more than 60; or Saturn, with 53. Even asteroids have multiple moons — including Sylvia, a 384-mile (617 km) space rock that boasts the twin satellites Romulus and Remus.
But Earth’s rep may might gotten a bump, thanks to a paper just published in the journal Nature. Our home planet may have just one lonely moon now, but long ago, like Mars and Sylvia, we had two. "Whether it’s right or not, I don’t know," says Maria Zuber, a planetary scientist at MIT who wrote an opinion piece accompanying the new study. "But I think it’s very plausible."
This diagram provided by Martin Jutzi and Erik Asphaug, University of California, Santa Cruz via Nature shows a simulation of four stages of a collision between the Moon and a companion moon, four percent of the lunar mass, about 4 billion years ago. Earth once had a second moon, until it made the fatal mistake of smacking its big sister, some astronomers now theorize. For awhile when the Earth was young, it had a big moon, the one you see now, and a smaller "companion moon" orbiting above. Then one day that smaller moon collided into the bigger one in what astronomers are calling the "big splat." (AP Photo/Martin Jutzi and Erik Asphaug, University of California, Santa Cruz via Nature)
The idea, cooked up by astronomers Martin Jutzi and Erik Asphaug, of the University of California at Santa Cruz, started out as an attempt to explain why our moon has so asymmetrical a surface. The part that faces us is relatively smooth, with vast expanses of ancient lava forming flat, dark, low-lying plains that earlier astronomers mistook for oceans. But when space probes first circled the moon in the early 1960s, scientists learned that the far side is mostly covered with rugged mountains and craters.
This artist’s rendering provided by Martin Jutzi and Erik Asphaug, University of California, Santa Cruz via Nature shows a simulation of a collision between the Moon and a companion moon, four percent of the lunar mass, about 4 billion years ago. Earth once had a second moon, until it made the fatal mistake of smacking its big sister, some astronomers now theorize. For awhile when the Earth was young, it had a big moon, the one you see now, and a smaller "companion moon" orbiting above. Then one day that smaller moon collided into the bigger one in what astronomers are calling the "big splat." (AP Photo/Martin Jutzi and Erik Asphaug, University of California, Santa Cruz via Nature)
Nobody has ever been able to explain with certainty why the moon should be so lopsided: maybe it had to do with some kind of massive impact that violently rearranged the surface, much like what happened to the asteroid Vesta. Maybe it was a slightly off-center core that caused the crust to be thinner on the Earth-facing half of the moon, which made that hemisphere more susceptible to lava bleeds.
But then Jutzi and Asphaug began thinking. "It looked to us a little bit as though the highlands on the far side accreted" — which is to say, they were added on top of the pre-existing surface. The astronomers thought a bit more, and realized that this idea was consistent with scientists’ beliefs about how the moon formed in the first place. Thanks to the analysis of moon rocks that were brought back by the Apollo missions, planetary scientists are pretty sure that our satellite was born billions of years ago when a Mars-size planetoid smashed into the young Earth.
The impact blasted off a cloud of debris from both of the objects and sent it spinning into space, where it eventually congealed into the moon. There could have been other, smaller pieces as well, says Zuber, but their orbits would have been unstable, causing them either to be flung away or to fall into Earth or the moon pretty much immediately.
Except, that is, if they happened to end up at a Trojan point — a place in the same orbit as the moon, but either well ahead of or well behind it, that’s gravitationally stable — or relatively so anyway. Just last week, astronomers announced the discovery of a Trojan asteroid leading the planet Earth around the sun. There’s no reason a Trojan moon couldn’t lead or follow our moon around the Earth.
Trojan Asteroid: Like a poodle on a leash, tiny asteroid runs ahead of Earth in orbit of sun
By Malcolm Ritter | YahooNews.ca / AP
Like a poodle on a leash, a tiny asteroid runs ahead of Earth on the planet’s yearlong strolls around the sun, scientists report.
The discovery of this companion, which measures only about 300 metres across, makes Earth the fourth planet in the solar system that’s known to share its orbit with an asteroid.
Imagine Earth and the asteroid travelling around a clock face, with the sun in the middle. Generally, the asteroid runs about two numbers ahead.
However, the asteroid sometimes ranges so far ahead that it’s on the opposite side of the sun from Earth, said Martin Connors of Canada’s Athabasca University in Alberta. He reports the work with colleagues in Thursday’s issue of the journal Nature.
Asteroids are giant space rocks that orbit the sun, and ones that share an orbit with a planet are called Trojans. Scientists had previously found a few for Mars and Neptune and nearly 5,000 for Jupiter. Spotting one in Earth’s orbit is difficult from the ground because the potential locations are generally in the daytime sky.
The newfound object, called 2010 TK7, was discovered last year by NASA’s WISE satellite. Connors and colleagues were able to focus a ground-based telescope in Hawaii on it in April, determining its orbit with enough precision to show it was a Trojan.
Donald K. Yeomans, manager of NASA’s Near-Earth Object Program Office, who didn’t participate in the discovery, agreed that the asteroid is a Trojan. Most scientists suspected Earth had them, he said, and "I would guess there’s others."
"Stockholm’s not burning" 2013 05 25 Video here: ctvnews.com
With international media swooping on the Stockholm riots from every angle, The Local’s Oliver Gee explains why Stockholm’s not burning, and how the story has been blown out of proportion.
Day five into the Stockholm riots and the world, as viewed from our Stockholm office, has gone crazy. The UK and the US have issued travel warnings for ...
Britain’s MI5 Connection to Woolwich Slasher Michael Adebolajo 2013 05 25
What a difference a day makes…
People are still in a state of shock and disbelief following a recent attack branded as a ‘terrorist” event by the UK media establishment and echoed in political corridors. It seemed so random…
Aside form appearing random, the brutal Woolwich attack this past week was one of the most bizarre and strangest of its kind yet, ...
Somali reporter: Swedish journalists are more dangerous than al-Shabab 2013 05 25 This article is translated by google and slightly improved for clarification.
This short story (the tip of the iceberg) is a great example of the media climate in Sweden and the lack of proper Journalism. An extremely dangerous one sided view is constantly presented by the government subsidized media.
Swedish journalists and their lies are more dangerous than the cruel Somali terrorist ...
Germany’s Merkel shrugs aside new book about communist-era past, says she never hid anything 2013 05 25
Chancellor Angela Merkel has shrugged aside a book that suggests she may have been closer to East Germany’s communist system than previously thought, saying she’s never hidden anything.
The 58-year-old Merkel grew up in East Germany and entered politics as communism crumbled in 1989. It’s long been known that, like many, she joined the communist youth organization. She has said she ...
‘Lack of public debate on immigration caused Stockholm riots’ 2013 05 25
Mishra Mrutyuanjai raises some points that we discussed with Mikael Jalving about in our Red Ice Radio program, in January earlier this year.
Sweden should put its political correctness aside and start an open debate on immigration as it’s the only way to avoid a repeat of the Stockholm riots, Mishra Mrutyuanjai, Swedish Democrats movement member, told RT.
Stockholm is reeling as ...