Sept 22 - Equinox Today or Tomorrow

September 22 Equinox Today or Tomorrow by:

Equinoxes at right. Solstices at left. In each of the images, Earth's rotational axis is perpendicular (straight up and down), with the North Pole at top and South Pole at bottom. Images via Geosync.

All you need to know: September equinox The Northern Hemisphere's autumn equinox - and Southern Hemisphere's spring equinox - is today or tomorrow, depending on your time zone. It falls on September 23 at 07:50 UTC; translate UTC to your time. Our ancestors knew that the sun's path shifts across the sky. They knew that the length of daylight and location on the horizon of the sunrise and sunset also shift in a regular way throughout the year. They built the first observatories - like those at Machu Picchu in Peru - to track the sun's progress. Today, we know each equinox and solstice is an astronomical event, caused by Earth's tilt on its axis and orbit around the sun. Happy fall or spring, y'all. Here's all you need to know. An astronomer contemplates the equinox You can think of the equinox not as a whole day, but as a point along Earth's orbit. Want to understand that better? Guy Ottewell offers some insights. Read more. Year's fastest sunsets happen around the equinoxes We're talking about the actual rate at which the sun sinks below the horizon. It's faster around the equinoxes than at any other time. Read more. The 2nd-fastest pulsar, now with gamma rays Pulsars are the compact remnants of supernovae. They have strong magnetic fields and rotate rapidly. This one is spinning 707 times a second! Astronomers just discovered this pulsar is emitting high-energy gamma rays. Read more.

EarthSky lunar calendars are back in stock We're guaranteed to sell out, get one while you can! Your support means the world to us and allows us to keep going. Purchase here.

Equinox sun is over Earth's equator This illustration by Tau'olunga via Wikimedia Commons shows the day arc of the sun, every hour - during the equinoxes - as seen on the celestial dome - from the equator. Also showing twilight suns down to -18° altitude. Note the sun at the zenith at noon and that the tree's shadow is cast straight down. That is - as seen from the equator on the day of an equinox - a tree stands in the center of its own shadow. Read more.

Where's the moon? Last quarter View at EarthSky Community Photos. | Dr Ski in Valencia, Philippines caught the last quarter moon shortly after it rose around midnight last night. This moon phase is perfect for helping you envision the location of the sun ... below your feet. The moon reached its last quarter phase at 2:41 UTC today. In the coming week, watch for it to rise in the east in the hours after midnight, waning thinner each day. Read more. Thanks, Dr Ski! Submit your photo to EarthSky here! Did a friend forward EarthSkyNews to you? Click here to get your own subscription!

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