Cruithne - is it our second moon?, page 1

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Topic started on 18-8-2004 @ 06:13 AM by infinite

Well, Cruithne is earths second moon, sort of. Some say it is, others say it cannot be due to its orbit. But it is an interesting to read into this topic. My view on the matter, is pretty grey, i don't know what to make on this "second moon", its orbit doesn't fit the pattern of our moon. But recently, a third object has been found in our orbit which has been labelled as our third moon, but NASA nerds are saying that the third moon is probably space junk.

Now i have searched hard for some info to understand this object in space.

Earth has a second moon, of sorts, and could have many others, according to three astronomers who did calculations to describe orbital motions at gravitational balance points in space that temporarily pull asteroids into bizarre orbits near our planet.

The 3-mile-wide (5-km) satellite, which takes 770 years to complete a horseshoe-shaped orbit around Earth, is called Cruithne and will remain in a suspended state around Earth for at least 5,000 years.

Cruithne, discovered in 1986, and then found in 1997 to have a highly eccentric orbit, cannot be seen by the naked eye, but scientists working at Queen Mary and Westfield College in London were intrigued enough with its peregrinations to come up with mathematical models to describe its path.

Second moon

This diagram is a view from above the solar system. The Sun is the dot in the centre, the pinkish circle is the orbit of Mercury, the green is Venus, the blue is us, the Earth and red shows the orbit of Mars. And there is the yellow orbit of asteroid Cruithne - it's a massive track that goes out as far as Mars and in as far as Mercury! However, the single most important thing to notice is that Cruithne's orbit is NOT around the Earth.

Another fact is that if you watched over time this yellow line would wander to the right and to the left along the orbit of the Earth once every 385 years! At times the orbit brings Cruithne underneath the south pole of the Earth (40 times further away than the Moon), and at other times it can be on the other side of the Sun. It's all terribly complicated and my calculator blew up last time I tried to work out where Cruithne actually was!

Needless to say you cannot call Cruithne second a moon of the Earth just because it shares the same orbit as the Earth. If it went around us then it's a different story. So what can we call this strange world? Technically and correctly Cruithne is (sorry about the tech-speak) a Co-orbital Near-Earth Asteroid. But if we call it a Co-Orbital Near and Crossing Earth Asteroid, then it becomes a CONCA (pronounced Con-ker), and if that gets picked up by big sceintist people then I've just invented a new world-famous space mnemonic!

And by the way there are now two more asteroids which travel in the same way as Cruithne, called excitingly 1998 UP1 and 2000 PH5 - that brings the total to 3 CONCAs so far.

Asteroid 3753 CRUITHNE

[edit on 18-8-2004 by infinite]

reply posted on 18-8-2004 @ 06:38 AM by Kano

The space junk one you are referring to is probably J002E3, first noticed 3rd sept 2002.

www.space.com...
www.space.com...

Cruinthe isn't quite a moon as its not locked in to Earth orbit, just dragged into an orbit similar to Earths by our gravity. Until it can escape again. From memory there are a couple of other similarly captured natural objects with orbits near Earth.

reply posted on 18-8-2004 @ 06:42 AM by infinite