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Author Topic: What is the time based off?  (Read 4727 times)

Blxz

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What is the time based off?
« on: May 01, 2011, 05:30:29 AM »
I am curious. Is the time that is set for the universe at GMT or american or european time or anywhere in particular?

I'd like to set up the solar system exactly 'as is' right now and just leave it running at real time. Currently I am living in Japan which is GMT 9+ and I want the earth rotation to be accurate so its dark there at the same time it gets dark here.


EDIT: Ahh, no matter. The simulation isn't accurate. Unless of course by 2025 mercury will be shooting out past Jupiter at escape velocity with both Venus and Earth joining it within 100 years of the start date. This is with nothing edited either. I'll try again with the accurate physics turned on.

EDIT2: Nope. With 'accurate mode' turned on mercury should already be long gone at todays current date. Took less than a year or 2 to shoot off. Pity, I've always liked mercury.

EDIT3: Of course it makes sense now. As I speed up the game the accuracy of the projection decreases. Makes sense.
« Last Edit: May 01, 2011, 06:53:52 AM by Blxz »

atomic7732

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Re: What is the time based off?
« Reply #1 on: May 01, 2011, 11:05:13 AM »
It should be UTC (GMT), as thats what Horizons goes off of...  If you'd want to see lets say Saturn's moons now... You'd have to run it at like... a slow step so Saturn's moons don't fly off, and by the time you rea ch the current date, you would have ran it for like 2 months.

Aephion

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Re: What is the time based off?
« Reply #2 on: May 05, 2011, 11:55:26 AM »
That's something I'd like too. Stepping to times / dates (and reversing time!!).
Especially the latter, because somethimes something is looking just, too awesome, and then you can't reverse time :<

Dan Dixon

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Re: What is the time based off?
« Reply #3 on: May 05, 2011, 01:12:52 PM »
You can hit the 'R' key to reverse velocities, which is similar to reversing time. Or select certain bodies and hit the "Reverse Velocity" button.

All astronomy programs that are not gravity simulators (so almost all of them) use ephemeris and can calculate a position given any specific time.
http://en.wikipedia.org/wiki/Ephemeris

Because this is a gravity simulation where the calculations of step are dependent on the ones previous to it, adding a feature that lets you reverse time is pretty complicated.

You can hit the disk icon in the upper right to save the state of the simulation and the load it again with the Restart button. They may help.