Celestia Forums

For anyone interested the Documentary program “If Earth Had No Moon” is on tonight at 10:00 PM Pacific Time on the Discovery channel. You will need to check your local listing for your time zone. Discovery channel always plays these twice a night so they should play it again at 1:00 AM Pacific Time as well.

Don.

?!

is this a TV version of the book?

Not sure if it was a book.

Neil F Comins did a book called 'What if the moon didn't exist' that explored this scenario, along with others such as 'what if a black hole passed through the earth', 'what if the sun was brighter', and other interesting alternatives. I think it's still available.

Just noticing, in celestia when you go back in time the moon dosent get closer to the earth (The rate at which the moon gets further away is 1 inch per year, so if you revurs time the mmon should get closser by 1inch every year) the moon should end up at around 14000 miles away from the earth (If you revurs time in celestia) after it has mooved to this distance it should not be there anymore, because thats the distance that the moon formed at (so it couldent get any closser) if you still went back in time a ring should replace the moon (the ring being the debri that formed the moon) and if you centenu to revers time the ring should also dissipear (after reversing time about 100 years ferther)

could smeone make an xyz for the moons orbit path starting when the moon was 14000 miles above the earth, and have it spiril out at a rate of 1 inch per year untill it gets to where it is now?

I would do the rest if i could get that

Star lion
Celestia is far from perect at this point. If what you were asking was built in then the Earth should also be spinning once a day at an 18 hour period as well. Of coursse you could write this up as a script file and plug it in.

Don.

Hmm, sonds good
But how do you make a script that alters the rate at which the earth spinns? And how do you get the moon to go ferther away as time goes on without an xyz file?

The furthest back in time that Celestia goes is only about 3 million years. That's enough time for the Moon to be about 120 km closer to the Earth than it is now (assuming a recession of 0.04 m/yr, wthe same as it is now) - which probably isn't even noticeable in Celestia.

I do infact remember reading the book "What if the Moon did not exist?" which featured a picture of the moon with a red X through it on the cover. There were several scenarios that were discussed such as both a light-weight and more massive Earth, and featured such imaginative (or not) names like Pietel and Lunholm. I suppose it was a good book though I've long since lost it. Did not know it was a TV show however.

the show has nothing to do with that book. it's more like that 1000 worlds show discovery did about the moons of the gas giants.

Star Lion wrote:Hmm, sonds good
But how do you make a script that alters the rate at which the earth spinns? And how do you get the moon to go ferther away as time goes on without an xyz file?

If you can write an xyz file about 10GB in size, or if you can somhow get Horizons to go back 3 million years, then it might work... (and the difference would be barely noticeable, like the Evil Dr. said.

xyz files aren't designed to do something like that... They record a position in space at a certain time, and are only as accurate as the number of points in each time period.

A more interesting experiment might be to show Phobos' orbit slowly decay, until it crashes into Mars in a few million years. (Yes folks, it will happen!!)

eros wrote:the show has nothing to do with that book. it's more like that 1000 worlds show discovery did about the moons of the gas giants

No, that's a different show you're thinking of. I've seen both of them, and aalthough it was a good while back I remember them as being both pretty good.

Don't forget Triton's inevitable date with destiny within Neptune's Roche Limit. That would be one spectacular breakup to witness.

Apollo7 wrote:Don't forget Triton's inevitable date with destiny within Neptune's Roche Limit. That would be one spectacular breakup to witness.

How could I forget that...?! (SL9, eat your heart out...) Adrastea, Metis, NINE of Uranus' minor moons and a few small neptunian ones will all be gone in a few million years too... Anyone know which is supposed to go first, and when?

In geological/universal timescales, that's a lot happening in a short space of time. Given this, we can assume that solar systems are very dynamic in terms of mutability over a given timescale.

Obviously we can see the future of certain solar system bodies, but how about the past? What strange and mysterious denizens stalked the solar system in epochs long gone? What catastrophes may our ancestors have witnessed? (Not wishing to go all Velikovsky on you )

Another concept to add to my solar system generator...this is gonna take ages

Cormoran