Saturn & Jupiter

[Shane Galvin]

Who out there knows how long it takes for the light to travel from Saturn & Jupiter to the earth?
Im having a discussion with a guy from work who thinks he knows everything & would like the right answer to put him in his box.
Cheers

[acropolite (Phil)]

That figure would vary depending on where in it's orbit the particular planet is relative to earth. This site will give you some info on the distances, you can calculate the time taken for light to get here with simple arithmetic.

[erick (Eric)]

Depends on where the Earth and the Planets are in their respective orbits.

If I have the numbers right:-

Between 33 min and 54 min from Jupiter and between 67 min and 92 min from Saturn.

[erick (Eric)]

Originally Posted by AGarvin

......Hmm, hope i've got my numbers right.....

Originally Posted by erick

........If I have the numbers right:-.........

confident of our maths, aren't we!

[AJames]

Shane

Try JPL's Horizons at http://ssd.jpl.nasa.gov/horizons.cgi#top.

Here you can input the planet required by hitting [change], and it will give you the light times. Ie. Saturn is 699, Jupiter 599, and it will give you want you want by default. (Explanation is listed below.)

Using the defaults will give you the light-times - hence distance by the hour for the current day. (You can change the span times with ease)

Make sure the Observer Location is "Geocentric" (500) - not Heliocentric as you will be standing on the Sun. [ actually within the Sun for the pedantic]

You can also use the Table Settings for the parameters you want.

Andrew James

Note: blow him out of the water, mate!

[erick (Eric)]

Which led me to an interesting question. Apart from the rotation of the earth (OK, and clouds/smoke etc!), is there ever a time before the solar system disintegrates that the light from Jupiter and Saturn is not visible from the earth? Hmmmm?

Well, it seems our respective orbital planes ensure that, for some time to come, neither Jupiter nor Saturn are occulted by the Sun. But I persisted.

Be in Hawaii in the morning of 21 July 2152, solar filter attached, and you will observe Saturn move behind the Sun!

Remember to send me a postcard!

Drat! Just remembered - occultation by the Moon!

[AJames]

How about the night side of Jupiter and Saturn that is facing away from the Earth!
Any lightning storms or aurorae are always perpetually invisible to observers.

[erick (Eric)]

Stop it! I'm going to get a sore head if I have to keep hitting it!