Why are Venus and Jupiter so bright?
9 comments Print Me Email to FriendTonight is Friday, Nov 21 2008
The planets Venus and Jupiter – the two brightest starlike lights in the sky – beam in the southwest at dusk and early evening. They will be drawing closer together as this month passes, coming closest on November 30 and December 1, when a slim crescent moon will also be nearby. For the best view of these blazing beauties, find an unobstructed horizon in the general direction of sunset. Venus and Jupiter will be to the left of the sunset point. They will appear rather low in the sky, setting roughly 2.5 and 3.5 hours after the sun, respectively.
After the sun and moon, Venus and Jupiter rank as the third and fourth brightest heavenly bodies, respectively. Among starlike objects, they rank first and second. You really can’t mistake them for anything else! They appear bright and beautiful because the cloud cover on these worlds efficiently reflects sunlight. Venus reflects 65% of the sunlight that hits its surface and Jupiter reflects 52%. In contrast, our rocky moon reflects 12% of the incoming sunlight whereas the rocky planet Mars reflects 15%.
Venus, the second planet outward from the sun, looks brilliant in our sky, because this world is close both to the sun and to Earth. But Jupiter, the fifth planet outward, moves in an orbit that is 7 times farther out than the orbit of Venus. At that distance, the intensity of sunlight hitting Jupiter is only about 1/50th of what it is on Venus.
Nonetheless, Jupiter shines brightly in our sky, because its huge reflective surface covers some 130 times more area than Venus’ surface does!
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Luke,
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Bruce
hey i know u
Hi. I follow your website whenever I can, and in the last 6 months have learned a great deal.
I have heard on the radio that you can see the space station passing over at night, and even by day. Can you suggest how I can see it? I live in Portugal, so have lots of clear skies both day and night.
Thanks again for your site,
Regards, Bill Ure
Bill,
Yes, you’ll have the International Space Station (ISS) flying through your sky in Portugal every night from Friday, November 21, to Friday, November 28. After that, the ISS will again pass through your sky every night from December 4 to December 10. Some nights, you can see the ISS pass over twice.
Tonight, on Friday, November 21, the ISS will cross the sky in Lisbon, Portugal, from about 7:05 to 7:07.5 p.m. Portuguese Winter Time. The ISS will be at its brightest best on Saturday night, November 22, from about 5:55.5 to 6:01 p.m.
For more information, I highly recommend this Heavens Above Satellite Visibility site. Click on “from data base,” then click on “Portugal”. Then write in the name of your town, and hit the “Submit” button. You’ll have complete information on the International Space Station and other satellites as well.
Best of luck!
Bruce
My five year old daughter looked out of the window just now (17:07) and announced that she could see Venus, the “wishing star.” I pointed out Jupiter above it and she wanted to know more about astronomy. I remembered hearing about the proximity of the planets on the radio (WAMC Albany) and came to the website to read more for my daughter. She was thrilled by the diagram of what she was seeing in real life and listened attentively as E read her the information posted with it. Thank you so much for making good science accessible to the community, especially budding scientists like my five year old.
Yeah i went outside and I saw the planets!!! They are like the brightest planets ever!! See my mommy saw it first earlier this week and told my grandfather. So today I steped outside and I could see it throught the trees!! AMAZING That is the reason I want to be an astronomer. Trust me I’m smart… Be looking for me…
Heidi & Tatiana,
Nothing like a grand sky scene to bring mothers and daughters together! And a grandfather, too. Yes, I’ll be looking out for you up-and-coming scientists.
Bruce