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A Guide to the Night Sky: March 2017 - Tre Gibbs LLAS


A Guide to the Night Sky
March 2017 

By Tre Gibbs, LAAS

Goodbye Venus, Hello Jupiter!

As we welcome the return of Spring this month, there are some interesting changes happening in the night sky. The planet Venus, which has been prominent in the southwest just after sunset all winter long, continues her fast decent towards the sun. By mid month, she will no longer be visible in our evening skies and by month’s end, Venus will be on the other side of the sun, appearing as The Morning Star in our eastern, pre-dawn skies. Mars, The God of War, is following Venus – though obviously taking his time. By month’s end, Mars will still be barely visible very low in the west just after sunset, but will drop quickly below the horizon as Earth continues her daily rotation, carrying us away from the light of the Sun.

As we bid Venus a temporary farewell from our evening skies, we welcome the return of the planet Jupiter! Visible just above the eastern horizon around 10:00 pm, Jupiter is the fourth brightest object in the sky, after the Sun, Moon and Venus. Jupiter is interesting for many reasons. First of all, it’s a giant ball of gas – there’s no hard surface on which to land anything. Secondly, it’s MASSIVE. Almost eleven “side by side” Earth’s would span Jupiter’s equator. Thirdly, at it’s closest point, Jupiter is roughly 365 million miles away from Earth. How far is 365 million miles? Here’s one way to grasp such an abstract distance; when you look at Jupiter, you are seeing it as it was roughly 33 minutes ago, since that’s how long it took the light from Jupiter to reach your eye. On the evening of the 14th, look for Jupiter just above and to the right of the moon, both low in the east around 10:30 pm and gradually climbing higher as the night continues.

Speaking of the moon, this month’s full moon, the Full Worm Moon, is on the 12th, technically at 7:54 am. The name “Full Worm Moon” is due to the time of year when ancient people and tribes noticed the ground beginning to soften and earthworm casts reappearing, thereby inviting the return of the red breasted robins, which means Spring!   

…and speaking of SPRING, the Vernal Equinox happens this month! On March 20th at 3:21 am, we herald the official return of Spring in the Northern Hemisphere! The word Equinox is Latin for “Equal Night”, so, this is what’s happening - the sun’s path in the sky has been moving northward since the Winter Solstice (December 21st) and on the 20th of this month, the sun will rise due east, set due west and as a result, we’ll receive equal amounts of day and night – about 12 hours of each. From this point until June 21st, the sun’s path in the sky keeps moving northward and the length of daylight continues to increase, as the amount of night continues to decrease.

In last month’s article, I promised a few words about the planet Saturn, so… Saturn, like Jupiter, is a giant ball of gas, but this one is known for its amazing and beautiful ring system. And if you thought Jupiter was far, Saturn is more than twice as far - roughly 840 million miles away at it’s closest point to us (remember, we’re all traveling around the sun at different speeds, in different orbits), which is why it looks so small and nondescript to us here on Earth. In terms of light distance, when you see Saturn in the sky, the light from it took about an hour and forty five minutes to reach your eye! Saturn rises around 3:30 am this month, so I’ll write more about it in the coming issues, as it slowly makes it’s way into our mid to late evening skies.

Until then, don’t forget to set your clocks forward one hour on the 12th. Oh, and show your kids the planets! The info in these articles can help – and the experience they get from you will stay with them forever. Keep looking up!