Summer will transition into fall tomorrow (Sept. 22), and the Slooh Community Observatory is celebrating this celestial event with a live webcast.
The 45-minute Slooh equinox webcast will begin at 10 a.m. EDT (1400 GMT), and you can watch it live on the Slooh website here. The webcast will feature views of the sun (its position in the sky can reveal the time of year). You can also watch the webcast at Space.com, courtesy of Slooh.
The Earth's seasons are more than just a convention of the calendar; they're determined by the tilt of the Earth on its axis. When one half of the planet is tilted toward the sun, that hemisphere experiences summer, while the other hemisphere is tilted away and experiences winter. The transition into fall in the Northern Hemisphere is thus a transition into spring in the Southern Hemisphere. [Season to Season: Earth's Equinoxes & Solstices (Infographic)]
The autumn equinox marks a midway point in this planetary tilt, halfway between the longest day of the year (the start of summer) and the shortest day of the year (the start of winter) for the Northern Hemisphere.
According to a statement from Slooh, the webcast host, Paul Cox, "will be joined by a series of expert guests," including Gail Higginbottom, a lecturer from the school of archaeology and anthropology at the University of Adelaide in Australia, who will discuss her research on the great stone circles of the United Kingdom and their connection to the movement of the sun and the moon.
The webcast is a partnership between Slooh and the publishers of the annual reference book and website "The Old Farmer's Almanac." Cox will also be joined by Janice Stillman, current editor of the almanac. Stillman will discuss some of the long-held cultural beliefs and traditions surrounding the equinox, including the rumor that it's possible to balance an egg on its end during the event.
Slooh astronomer and astronomy editor for "The Old Farmer's Almanac," Bob Berman, will also join the broadcast to "break down the basics of the equinox," including why the split between day and night aren't actually equal and why the equinox doesn't take place at the same day and time each year.