Anonymous
Anonymous asked in Science & MathematicsAstronomy & Space · 7 years ago

# Stephen Fry said according to NASA earth has approximately 18000 moons (stellar bodies not satellites) ?

Stephen Fry said that on QI in season 11. And that only because of new equipment Nasa has found all those moons because they were to small to see with the naked eye or telescope.

Update:

I have link with the video here and if I had a link to a NASA page I wouldnt be asking this question.

Update 2:

At 2:20 min.

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• 7 years ago

The work to which Stephen Fry refers can be accessed here

http://arxiv.org/abs/1112.3781

I think he and his researchers have misinterpreted the study (which was conducted by Robert Jedicke and some French collaborators, so not really 'NASA').

The computer simulations they conducted did result in just over 18,000 temporarily captured objects (TCOs) however what the authors were attempting to work out was the frequency with which objects in near-Earth heliocentric orbital space move into temporarily captured orbits. They used a model to select about 10 billion initial test particles in orbit space (a,e,i), from which 10 million particles with some likelihood of Earth capture were followed by orbit integration and from this they found slightly more than 18,000 objects that were captured for at least one orbit in their simulations.

The key result is then the probability of an object in a given heliocentric orbital space (a,e,i) becoming captured. They combine this computed result with various models of the Near Earth Object population to come up with the population of captured objects and use the computed lifetimes of capture to compute a steady-state population.

Their favoured result is that the Earth-Moon system has on average at any given time one (1) captured object around 1 m in size. There will be more at smaller size ranges so I guess you can still get to a population of 18,000 by setting your size cut-off appropriately (perhaps at around 1 cm).

I'd thus argue that the 'correct' answer is '2', Luna plus a single 1-m size captured rock at any given time.

• Anonymous
7 years ago

Stephen Fry is not a scientist, so whatever he says has to be taken with a grain of salt (he is a comedian after all).

Its fine to claim NASA said something, but before anyone believes it we need a link to the article or the web page that supports it. Funny I don't see anything about thousands of moons on NASA's website anywhere...

And if they are too small to see with the naked eye or telescopes, how did NASA detect them since they use telescopes...?

• ?
Lv 7
7 years ago

It would make sense that the Earth's gravitational field would have pulled in many asteroids and other chunks of material. It's called accretion. Gravity didn't stop existing after the main period of planet formation.

I'm just not sure of the gist of your question.

• 7 years ago

Thanks for the link. Now, much as I enjoy QI, I don't have time to watch a whole episode. How about a time also?