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leokor
2011-Feb-25, 09:08 PM
Hi,

How can I find out if Earth is above or below the Venus' orbital plane on a particular date? Specifically, I'm interested in June 14, 2976.

Leo

Githyanki
2011-Feb-26, 12:09 AM
Maybe try Celestia?

Romanus
2011-Feb-26, 02:58 AM
JPL's HORIZONS ephemeris may also be useful...

http://ssd.jpl.nasa.gov/?horizons

There are also ways you can cheat a little; for instance, working backward by breaking the time period into 8-year blocks (five synodic periods, in which Venus and Earth very nearly match locations).

Edit: On second thought, this is too long a time frame to use the eight-year "rule", which is not exact...

tony873004
2011-Feb-26, 10:21 PM
I just did this in Gravity Simulator.
On June 14, 2976, Earth will be below Venus' orbital plane. Ascending, it will cross on June 17. On the June 16, the planes will be close enough that Venus' inferior conjunction with the Earth on that date will produce a solar transit.

Numerical simulations are only as good as their input. A small error can grow quite a bit in 965 years. So the validity of my results depends heavily on how accurately we know the positions velocities and masses of the solar system's bodies.

Just curious... why the interest in that particular date?

leokor
2011-Feb-27, 01:51 AM
On June 14, 2976, Earth will be below Venus' orbital plane. Ascending, it will cross on June 17. On the June 16, the planes will be close enough that Venus' inferior conjunction with the Earth on that date will produce a solar transit.

Thanks! I was under the impression that the inferior conjunction would fall on June 14. June 16, then, with Earth still a little below the orbital plane of Venus? Good.

Would Venus still be visible in the evening of June 4, perhaps very low over the horizon?


Just curious... why the interest in that particular date?

That's for my science fiction story. Thanks again!

Leo

Centaur
2011-Feb-27, 03:32 AM
Hello, Leokor. I’m afraid there is no above or below in space. Australians do not fall from the Earth into the sky. However, we can speak of a planet being north or south of another planet’s orbital plane.

I’m utilizing the powerful and highly accurate Solex numerical integration program. On 2976 JUN 15 at 21 hr TT, Venus will pass southward through Earth’s orbital plane, while near the same time Earth will pass northward through Venus’ orbital plane. There will be a transit of Venus across the apparent disk of the Sun on JUN 16. Geocentric closest approach between centers will occur at 20:53 TT, which can be roughly estimated as 20:06 UT. Geocentrically at that time Venus' center will appear 0.236 south of the Sun’s center.

Your question about the visibility of Venus on JUN 04 greatly depends on your location on Earth. As viewed from Chicago’s Adler Planetarium on that date at 40 minutes after sunset, Venus will be 7.4 above the horizon.

I hope this helps. I wish you well with your story.

Centaur
2011-Feb-27, 03:44 AM
Please note that I had to correct a typo in my previous post regarding the number of minutes after sunset.

leokor
2011-Feb-27, 06:21 AM
I’m utilizing the powerful and highly accurate Solex numerical integration program. On 2976 JUN 15 at 21 hr TT, Venus will pass southward through Earth’s orbital plane, while at the same time Earth will pass northward through Venus’ orbital plane. There will be a transit of Venus across the apparent disk of the Sun on JUN 16. Geocentric closest approach between centers will occur at 20:53 TT, which can be roughly estimated as 20:06 UT. Geocentrically at that time Venus' center will appear 0.236 south of the Sun’s center.

So, at the time of the conjunction, Earth will be a tiny bit northward from the Venus' orbital plane. Thanks!


Your question about the visibility of Venus on JUN 04 greatly depends on your location on Earth. As viewed from Chicago’s Adler Planetarium on that date at 40 minutes after sunset, Venus will be 7.4 above the horizon.

Perfect. I suppose Texas won't be much different from Chicago in this regard.

Leo

Centaur
2011-Feb-27, 05:26 PM
So, at the time of the conjunction, Earth will be a tiny bit northward from the Venus' orbital plane. Thanks!


You’re welcome, Leo. First let me provide a minor correction that should not affect your concerns. While indeed Venus will pass southward through the Earth’s orbital plane on 2976 JUN 15 at 21 hr TT, the Earth will pass northward through Venus’ orbital plane 15 hours earlier at 06 hr TT. It is only during times near a June transit that these two events come so close to occurring simultaneously.

Centaur
2011-Feb-27, 05:31 PM
Perfect. I suppose Texas won't be much different from Chicago in this regard.


That would likely be true, Leo. It you tell me where in Texas, I can be more precise.

leokor
2011-Feb-27, 09:07 PM
While indeed Venus will pass southward through the Earth’s orbital plane on 2976 JUN 15 at 21 hr TT, the Earth will pass northward through Venus’ orbital plane 15 hours earlier at 06 hr TT. It is only during times near a June transit that these two events come so close to occurring simultaneously.

Fascinating. I'll keep that in mind. Perhaps I'll be able to use it somehow.

As to where in Texas, let's say the southwestern part, somewhere close to Presidio:

http://toolserver.org/~geohack/geohack.php?pagename=Presidio,_Texas&params=29_33_41_N_104_21_59_W_region:US_type:city

Leo

Centaur
2011-Feb-27, 10:03 PM
As to where in Texas, let's say the southwestern part, somewhere close to Presidio:


From Presidio, Texas on Tuesday 2976 JUN 04, the Sun will set at 20:57 CDT. Venus will set at 22:21 CDT. At 40 minutes after sunset, Venus will be at an altitude of 8.0 and an azimuth of 295, which is 25 to the north (right) of due west. Are you planning a good old Texas barbeque for your friends that evening?

leokor
2011-Feb-28, 12:26 AM
Are you planning a good old Texas barbeque for your friends that evening?

Alas, no smoke in an enclosed biosphere. That's what the Amish of the time do: they raise authentic Amish biospheres to maturity (takes about fifteen years, give or take), then sell them for installation off-planet. That way they can maintain their simple lifestyle close to earth in a nanotech-permeated world. One boy, however, ends up whisked to Venus through a peculiar set of circumstances.

Leo

kamaz
2011-Feb-28, 01:03 AM
From Presidio, Texas on Tuesday 2976 JUN 04, the Sun will set at 20:57 CDT. Venus will set at 22:21 CDT. At 40 minutes after sunset, Venus will be at an altitude of 8.0 and an azimuth of 295, which is 25 to the north (right) of due west. Are you planning a good old Texas barbeque for your friends that evening?

And that is why I love astronomy. Puts everyday things in proper perspective.

leokor
2011-Mar-15, 05:31 AM
Many thanks again. May I ask further what would be the distance between Earth and Venus on July 4, 2976?

Centaur
2011-Mar-15, 06:05 AM
Many thanks again. May I ask further what would be the distance between Earth and Venus on July 4, 2976?

0.3367 AU at 21:37 CDT

leokor
2011-Mar-15, 07:03 PM
Thanks! :)