solstice – Watch the Skies

December Solstice Brings Winter, Summer Seasons

In meteorology, Earth’s winter season for the Northern Hemisphere and summer season for the Southern Hemisphere began on Dec. 1, 2021. However, the December solstice brings in the astronomical winter and summer seasons, respectively, for the two hemispheres of our planet. This will happen on Dec. 21 at 15:59 UTC, which is 9:59 a.m. CST in the United States.

Summer solstice explanation — During the solstices, Earth reaches a point where its tilt is at the greatest angle to the plane of its orbit, causing one hemisphere to receive more daylight than the other. Credits: NASA/Genna Duberstein

Solstices come twice a year. For the Northern Hemisphere, the summer (June) solstice occurs around June 20-21, and the winter (December) solstice happens around Dec. 21-22. At the solstice, the Sun’s path appears farthest north or south, depending on which half of the planet you’re on. Seasons change on Earth because the planet is slightly tilted on its axis as it travels around the Sun.

Earth’s axis may be imagined as an imaginary pole going right through the center of our planet from “top” to “bottom.” Earth spins around this pole, making one complete turn each day. That is why we have day and night.

Although the tilt of the Earth as compared to the plane of its orbit around the Sun is more or less constant (23.5˚), at the December solstice, the Northern Hemisphere receives the most indirect sunlight, causing cooler temperatures. The Southern Hemisphere receives the most direct sunlight, causing warmer temperatures, so it is summer there. At the June solstice, this effect reverses and the Northern Hemisphere receives the most direct sunlight, causing warmer temperatures, and the Southern Hemisphere receives the most indirect sunlight, causing cooler temperatures.

The December solstice brings the shortest day and longest night of the year for locations in the northern half of the globe, like the U.S., while the southern half of the globe is experiencing its longest day and shortest night. Therefore, all locations north of the equator see daylight shorter than 12 hours and all locations south see daylight longer than 12 hours.

After the winter solstice in the Northern Hemisphere, the days will get longer and the nights shorter until the summer solstice on June 21, 2022, when things reverse. The March equinox on March 20, 2022, will mark the beginning of the astronomical spring season and the September equinox on September 22, 2022, will mark the beginning of astronomical fall.

The ancient cultures knew that the Sun’s path across the sky, length of daylight, and location of the sunrise and sunset all shifted in a regular way throughout the year. Additionally, people built monuments, like Stonehenge in England and the Torreon in Machu Picchu, Peru, to follow the Sun’s annual progress and predict its movements.

Today, we have even more information about the universe, and we celebrate the solstice as an astronomical event caused by Earth’s tilt on its axis and its motion in orbit around the Sun.

No matter where you are on Earth’s globe – this is your time to celebrate this seasonal change!

by Lance D. Davis

June Solstice Brings Summer, Winter Seasons

The June solstice gives us the green light to welcome the summer season in the Northern Hemisphere and winter season in the Southern Hemisphere. This happens June 21, 2021, at 03:32 UTC, but for us in North America, that’s June 20 at 10:32 p.m. CDT (UTC-5).

In meteorology, summer begins on June 1. Yet, June 21 is perhaps the most widely recognized day when summer starts in the northern half of our planet and winter starts in the southern half. This astronomical beginning of the summer season and long-held, universal tradition of celebrating the solstice have allowed us to treasure this time of warmth and light.

Along with marking the beginning of summer, this will also be the longest day of the year in the Northern Hemisphere. We will begin to see early dawns, long days, late sunsets, and short nights. On the solstice, our Sun will reach its highest point as it crosses the sky. Meanwhile, south of the equator, winter will begin!

The ancient cultures knew that the Sun’s path across the sky, length of daylight, and location of the sunrise and sunset all shifted in a regular way throughout the year. Additionally, people built monuments, like Stonehenge, to follow the Sun’s annual progress, to worship the Sun, and to predict its movements.

Today, we celebrate the solstice as an astronomical event caused by Earth’s tilt on its axis and its motion in orbit around the Sun.

Earth doesn’t orbit upright; its axis is always tilted 23.5˚ with respect to the Sun-Earth line, which is why we have seasons. During the June solstice compared to any other time of the year, the north pole is tipped more directly toward the Sun, and the south pole is tipped more directly away from the Sun. As a result, all locations north of the equator see days longer than 12 hours and all locations south see days shorter than 12 hours.

Enjoy the new season – whichever half of the globe you’re in!

by Lance D. Davis

March Equinox Brings 2 Seasons: Spring, Autumn

The March equinox – also called the vernal equinox – is the beginning of the spring season in the Northern Hemisphere and autumn season in the Southern Hemisphere. It arrives on March 20, 2021, at 09:37 UTC (Coordinated Universal Time) or 4:37 a.m. CDT (Central Daylight Time).

An illustration of the March (spring) and September (fall or autumn) equinoxes. During the equinoxes, both hemispheres receive equal amounts of daylight. Credit: NASA/JPL-Caltech

During this equinox, the Sun will shine directly on the equator with nearly equal amounts of day and night, about 12 hours. Throughout the world, the Northern and Southern hemispheres will get equal amounts of daylight.

Click to view larger. Credit: NASA/Space Place

The equinoxes and solstices are caused by Earth’s tilt on its axis and ceaseless motion in orbit. Think of an equinox as happening on the imaginary dome of our sky, or as an event that happens in Earth’s orbit around the Sun.

In the Northern Hemisphere, the March equinox will bring us earlier sunrises, later sunsets, softer winds, and budding plants. With the opposite season, south of the equator, there will be later sunrises, earlier sunsets, chillier winds, and dry, falling leaves.

If you’re in the Northern Hemisphere, start watching the Sun as it sets just a bit farther north on the horizon each evening until the summer solstice. Also, enjoy the warmer weather and extended daylight!

Happy Solstice, Skywatchers

It’s the first day of summer here in the Northern Hemisphere, and the first of winter in the Southern Hemisphere. Why the difference? It’s all about Earth’s tilt!

During the solstices, Earth reaches a point where its tilt is at the greatest angle to the plane of its orbit, causing one hemisphere to receive more daylight than the other. (NASA/Genna Duberstein)

Earth’s axis is an imaginary pole going right through the center of Earth from “top” to “bottom.” Earth spins around this pole, making one complete turn each day. That is why we have day and night, and why every part of Earth’s surface gets some of each.

Earth’s axis is always tilted 23.5˚ with respect to the Sun. Today, the north pole is tipped toward the Sun, and the south pole is tipped away from the Sun. The northern summer solstice is an instant in time when the north pole of the Earth points more directly toward the Sun than at any other time of the year.

The solstice—meaning “sun stands still” in Latin—occurs at 10:54 a.m. CDT.

Lunar Eclipse, Sprinkled With Fireballs

The 2010 solstice lunar eclipse is one for the books, but check out these images from two cameras in the Canadian all-sky meteor camera network.These cameras are similar to the ones used for observation at NASA’s Marshall Space Flight Center: all-sky, black-and-white, and detecting bright meteors, or fireballs. Below are two stacked images of the eclipse:

Stacked image of the eclipse using images taken every five minutes from McMaster University
between 6:32 and 9:32 UT.

A similarly stacked image, combining pictures every five minutes between 5:27-9:37;
it was taken from Orangeville, ON, Canada.

Just as a reminder, the eclipse event timings in UT were:

Partial begins: 6:33
Total begins: 7:41
Mid eclipse: 8:17
Total ends: 8:53
Partial ends: 10:01

So both cameras captured the full moon as it normally appears, then imaged it as it was eclipsed through the partial and total phases. Unfortunately, bad weather rolled in before the eclipse ended!

The Canadian cameras also detected meteors during the eclipse. Here are a few good ones:

The following two images were also taken from McMaster and Orangeville at about 7:38 UT, just before the total eclipse began, but after the partial eclipse had started. These pictures show an image of a meteor fairly close to the moon in the field of view.

The following three images were recorded from Elginfield, ON, Canada, McMaster, and Orangeville, respectively, at about 9:00 UT, just after the total eclipse phase ended, but before the partial eclipse ended. This meteor ablated by a height of 83 kilometers, or 52 miles.

Images courtesy of the Meteor Physics Group at the University of Western Ontario in London, ON, Canada
Text courtesy of Danielle Moser, NASA’s Marshall Space Flight Center, Meteoroid Environment Office

Cloudy Skies? You Can Still Watch the Lunar Eclipse!

Cloudy skies over much of the U.S. might make for challenging viewing tonight for the solstice lunar eclipse.

This screenshot shows a view of the skies over Marshall Space Flight Center in
Huntsville, Ala., at approximately 6:45 p.m. on Dec. 20. (See Current View)

To help work around the mercurial weather, here’s a list of web sites that are offering live web views. Many of these are located in parts of the country where the weather is clear – and you can still check out the Marshall Space Flight Center Web cam. We’ve had some breaks in the clouds, and we’re hoping for the best as the eclipse time draws closer. Check back on this page throughout the evening for added links. Happy viewing!

List of links – please check individual sites for their viewing times and instructions:

› SpaceVidCast Lunar Eclipse Coverage→
› WPBT2/Miami Science Museum→
› Lunar Eclipse by Coaster Storm’s Weather Center→
› South Florida Amateur Astronomers Association & The Fox Observatory→
› Columbus State University→
› Rothney Astrophysical Observatory→
› Night Skies Network, Jack Huerkamp→
› Astronomers Without Borders Camera Network→
› Lunar Eclipse from Santiago, Chile→

Note: All of the links above are to external sites controlled by organizations other than NASA.

Tonight is the Solstice Lunar Eclipse!

The first total lunar eclipse in two years will grace the sky the night of Monday, Dec. 20, and we want you to be there. Sure, it’s a school night, but with winter solstice and a new year upon us, what better time to gather your family and friends to see the moon in a new light?

At NASA, we’re pretty excited for this year’s lunar eclipse, so we’re offering a number of features and activities for astronomy buffs and moon-gazers alike. To learn about the science behind eclipses, visit NASA’s Eclipse page, where Mr. Eclipse provides information about viewing the eclipse from all over the United States.

Want to know more about the lunar eclipse? Lunar experts from NASA’s Marshall Space Flight Center will be hosting two live Web chats to discuss the eclipse. On Monday, Dec. 20 from 3-4 p.m. EST, Dr. Rob Suggs will answer your questions. Later on Dec. 20, make plans to stay “Up All Night” with astronomer Mitzi Adams at she answers your questions from midnight to 5:00 a.m. EST.

Starting now, you can subscribe to NASA JPL’s “I’m There: Lunar Eclipse” text campaign to connect with others in your area by texting us your viewing location and comments on the night of the eclipse. To sign up, text IMTHERE to 67463 and we’ll send you a reminder to go out and watch on Dec. 20 (message and data rates may apply).

Want to share or flip through photos of the eclipsed moon? Join NASA JPL’s lunar eclipse Flickr group and connect with other professional and amateur photographers as they capture the moon’s path through the Earth’s shadow. We’ll choose one lucky photographer to have his or her work featured as official JPL wallpaper at http://www.jpl.nasa.gov/wallpaper.

If you don’t want to brave the December chill, or if your weather doesn’t cooperate for lunar viewing, we have you covered! A live video feed of the lunar eclipse will be streamed online on Dec. 20. The camera is mounted at NASA’s Marshall Space Flight Center in Huntsville, Ala.

On Dec. 20 and 21, join the conversation on Twitter by including #eclipse and @NASAJPL in your lunar eclipse tweets, and you may even see them show up among our live comment stream on NASA JPL’s “I’m There: Lunar Eclipse” program.