September 18, 2022
Sunday, September 18, 2022
Next Saturday, September 24, is the Dark Sky Festival at Sequoia and Kings National Parks. There will be events happening during the day starting at 10 AM, including a keynote presentation by Kate Gunderson, a mechanical and aerospace engineer now in training to be an astronaut. At night will be star parties in two locations. The is hosting the more popular one at the back parking lot and another group will host a smaller one at the . Both take place from 9 to 11 PM Another star party site at was just added to the schedule. It'll be from 10 to 11 pm. New Moon will be on Sunday, so the sky is going to be filled with stars, nebulae, clusters, and galaxies on a very dark sky.
At 10 PM on the night of the 24th, Saturn will be nearly due south at the tail end of the Capricornus. Jupiter will be dazzling bright in the southeast below the Great Square of Pegasus. Jupiter is just two days shy of being at opposition鈥攄irectly opposite the sun. This particular opposition will be the closest Jupiter gets to Earth since October 1963. It will be a mere 367 million miles from Earth. Back to the night of the 24th: low in the east the beautiful cluster of the Pleiades will be just becoming visible鈥攁 gorgeous sight in a telescope. Also visible will be the double cluster at the head of Perseus. One cluster is much farther away from us than the other but nearly in the same direction, so they appear side-by-side on our sky. Mars won't rise until shortly before 10:40 PM if you had a nice flat horizon but it'll be about 11:15 when it becomes easily visible.
Before you head out to Sequoia, come to the evening public show at the Planetarium on Thursday, September 22. The William M Thomas Planetarium will show 鈥�Destination Mars: The New Frontier鈥� that describes the work being done to make the dream of getting humans to Mars a reality. Two Thursdays later, we'll be showing 鈥�Dynamic Earth鈥� on October 6 that describes the various parts of Earth's climate system. Tickets for both shows are still .
September 22 is also the date of the for this year. That date marks the time when the sun crosses the projection of Earth's equator on the sky鈥攖he 鈥攈eading southward toward winter. The day lengths are getting shorter and the sun is taking an ever lower path across the sky. Eventually, that will but there is some lag because land and water don't heat up or cool off instantaneously.
The oceans move a lot of heat energy, many terawatts of it, around the globe as does our atmosphere. from the energy from the sun. The Moon and the Earth are at the same distance from the Sun but due to the Moon's lack of an atmosphere. The ranges from about -280 deg F (鈥�173 deg C) at night to +242 deg F (117 deg C) during the day!
On September 26 at 4:14 PM, the will collide with the small asteroid Dimorphos which is orbiting the larger asteroid Didymos. Dimorphos is just 530 feet (160 meters) across while Didymos is 2,560 feet (780 meters) in diameter. Neither asteroid is ever going to hit Earth and the impact of DART into Dimorphos is not going to change that fact. However, the change of Dimorphos' orbit around Didymos will be much easier to measure than if we tried the redirection of a single asteroid's orbit around the sun. All sorts of computer simulations have been done to predict what will happen when DART rams Dimorphos but we need to test the computer models with an actual experiment. DART is the first Planetary Defense test mission and it's a simple test鈥攈ow well can we nudge an asteroid?
At the end of the month, a will be just above the red heart of Scorpius, the supergiant star . Look to the southwest about 45 minutes after sunset to see them. Also at the end of the month on September 29, I will be giving the inaugural talk for the . It will be broadcast using BC's livestream.
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Director of the William M Thomas Planetarium at 太阳城官网
Author of the award-winning website
