Cruithne

Submitted by: Gerry1of1 3 years ago in Science

How many moons do you think the Earth has? Are you sure?
There are 21 comments:
Male 37,882
@Gerry1: That graphic is what Cruithne`s orbit "looks like from Earth" and not it`s actual path...
I have bad news about Pluto...

@Draculya: Yeah, you`re right. And I also think Cruithne is WAY too small to be considered a "moon".
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Male 38,507

For Alan Davies the answer is always "blue whale"
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Female 2,415
I love QI... it`s so much fun watching Alan Davies freak out when his answers are deemed incorrect when they were supposed to be truths from earlier shows. :)
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Male 38,507

Next you guys will be saying Pluto is not a planet.
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Male 2,688
In a later episode, the same question is asked, and Alan (whom is the only one of the 4 panelists that is in every episode) says 2 and is given the buzzer again because Cruithne was later found to NOT be a true moon.
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Male 2,860
If i remember correctly this was all sorted out in a later series.
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Male 14,835
@5Cats "It is in orbit of BOTH the Sun and the Earth"

Nope. It is not in orbit around the earth. In fact it will not come close enough to be measurably affected by earth`s gravity until a brief series of orbits around the year 2292.

That`s no moon.


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Male 38,507


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Male 37,882
There are several "objects" which orbit the Earth aside from the Moon (Luna).

Some only stay a little while and then zoom back into space. All are VERY small.

I see @richanddead has mentioned this. :-)

Wiki Says: Cruithne
It is in orbit of BOTH the Sun and the Earth:



Because the Earth`s gravity affects it`s rotation around the Sun in a big way.
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Male 14,835
Not a moon. Quasi moon. Not even in earth orbit. Not the most interesting such quasi moon. Not even one of the natural temporary satellites sometimes in earth orbit.
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Male 4,746
I was going to mention that orbiting the Sun means it`s not Earth`s moon but I can see that others beat me to it.
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Male 7,031

A simple rule of thumb : it`s not technically a moon if it doesn`t generate werewolf transformations ...

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Male 197
Ah, but this information was corrected in a later episode of QI. He`s not wrong if he corrects himself! :)
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Male 4,079
Cruithne is call earth`s second moon but it is how you determine what is a moon. Earth actually has thousands of satellite rocks ranging from a pebbles to those a couple of miles across. We also have "temporary moons," such as RH120. It`s who is calling a satellite object a moon. Sometimes "the Moon" is not called a moon either, and it is said that Earth and "the Moon" are binary planets with no moons.
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Male 1,471
oh, i see i`m too late.. oh well, no matter..
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Male 1,471
It`s NOT a moon. It orbits the sun, not the earth. All you have to do to find that out is to go to wikipedia.

*sigh*
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Male 883
So yes, I do mock the wonderful Stephen Fry in that his information was false.
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Male 883
As-ter-oid


[quote">Cruithne is an asteroid in orbit around the Sun in 1:1 orbital resonance with the Earth. It is a minor planet in solar orbit that, relative to Earth, orbits in a bean-shaped orbit that ultimately effectively describes a horseshoe, and which can transition into a quasi-satellite orbit.[3"> It has been incorrectly called "Earth`s second moon".[2"> Cruithne does not orbit Earth and at times it is on the other side of the Sun.[4"> Its orbit takes it inside the orbit of Mercury and outside the orbit of Mars.[4"> Cruithne orbits the Sun in about 1 year but it takes 770 years for the series to complete a horseshoe-shaped movement around the Earth.[/quote">
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Male 4
Cruithne does not actually orbit Earth and therefore would not be considered a moon.
http://en.wikipedia.org/wiki/3753_Cruithne
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Male 7,775
I see none of you dare mock the wonderful Stephen Fry and his moon story.
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Male 38,507
Link: Cruithne [Rate Link] - How many moons do you think the Earth has? Are you sure?
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