Archive for May 24, 2018

05/24/2018 – Ephemeris – Jupiter is really BIG

May 24, 2018 Comments off

Ephemeris for Thursday, May 24th. Today the Sun will be up for 15 hours and 8 minutes, setting at 9:14, and it will rise tomorrow at 6:05. The Moon, 3 days past first quarter, will set at 4:24 tomorrow morning.

Jupiter is a big planet. How big is it? One could fit thirteen hundred Earths inside it. Even so Jupiter has the mass of only 318 Earths, so Jupiter is made of lighter stuff than the Earth, including a lot of hydrogen and helium. NASA’s Juno spacecraft is currently orbiting Jupiter, working that out. Still, Jupiter is massive. The late science and science fiction writer Isaac Asimov wrote that the solar system consists of the Sun, Jupiter and debris. Jupiter contains more than twice the mass of all the other planets and asteroids combined. Jupiter is also surrounded by a huge set of radiation belts, lethal to all but the most radiation hardened spacecraft. And that goes for would be astronauts too.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Planet size comparison

Planet size comparison. Note that even though Saturn looks almost as large as Jupiter it is less than 30% of Jupiter’s mass. From