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FAQs

How to watch a total eclipse of the moon

Total lunar eclipse mosaic by eclipse master Fred Espenak.   Visit his page for the April 14-14 eclipse.

Total lunar eclipse mosaic by eclipse master Fred Espenak.

The April 4, 2015 total lunar eclipse comes in the morning for North America, and in the evening for Eastern Asia, Indonesia, New Zealand and Australia. Here’s what to look for.

What is a Blood Moon?

This is what a total eclipse looks like.  This is the total eclipse of October 27, 2004 via Fred Espenak of NASA, otherwise known as Mr. Eclipse.  Visit Fred's page here.

This is what a total eclipse looks like. This is the total eclipse of October 27, 2004 via Fred Espenak of NASA. We astronomy writers often describe a totally eclipsed moon as appearing ‘blood red.’ But Christians have a different definition for Blood Moon.

A lunar tetrad – four total lunar eclipses in a row – began a year ago. The next eclipse in this tetrad will take place on April 4, 2015.

Video: What is a pulsar?

A pulsar is a rapidly spinning neutron star which is the small, incredibly dense remnant of much more massive star. How dense? A teaspoon of matter from a neutron star weighs as much as Mount Everest.

What is a Dyson sphere?

View larger. | Here is a completely fantastic artist's concept of a Dyson sphere.  I like it.  Notice the little moon on the left side, being ravaged for raw materials.  Via FantasyWallpapers.com

View larger. | A fantastic artist’s concept of a Dyson sphere. The image is called Shield World Construction, and it’s by Adam Burn.

Proponents of solar power know that only a tiny fraction of the sun’s total energy strikes the Earth. What if we, as a civilization, could collect all of the sun’s energy? If so, we would use some form of Dyson sphere, sometimes referred to as a Dyson shell or megastructure.

Why does Earth have four seasons?

Photo credit: Jane Wildoner

Photo credit: Jane Wildoner

A Friday FAQ specially selected for equinox day.

Many believe Earth’s changing distance from the sun causes the change in the seasons. But that is not the case.

When is the next supermoon?

What most call a Blue Moon isn't blue in color. It's only Blue in name. This great moon photo from EarthSky Facebook friend Rebecca Lacey in Cambridge, Idaho.

Moon photo is from Rebecca Lacey in Cambridge, Idaho.

According to the definition of supermoon coined by Richard Nolle 30 years ago, the year 2015 has a total of six supermoons. They are the new moons of January, February and March and the full moons of August, September and October. The September 28, 2015 full moon will be the closest supermoon of 2015. The next supermoon – on March 20, 2015 – will cause a total eclipse of the sun! Follow the links inside to learn about the supermoons of 2015.

Why beware the Ides of March?

Image credit: veraukoion

Image credit: veraukoion

If you have heard of the Ides of March, you know you’re supposed to beware them. Why? In ancient Rome, the ides of March were equivalent to our March 15th. You probably know of the Ides of March thanks to William Shakespeare. In his play Julius Caesar, a soothsayer – or fortune teller – says to Caesar: Beware the Ides of March.

What are star trails? How can I capture them?

A two-hour-and-15-minute star trail image from March 21, 2014.  Our friend Ken Christison in North Carolina captured this image.  He wrote,

A two-hour-and-15-minute star trail image from March 21, 2014. Our friend Ken Christison in North Carolina captured this image.

What are star trails? They are the continuous paths created by stars, produced during long time exposure photographs, as shown on this page. In other words, the camera doesn’t track along with the stars’ apparent motion as night passes (actually caused by Earth’s spin under the sky). Instead, the camera stays fixed, while, as the hours pass, the stars move. The resulting photos show the nightly movement of stars on the sky’s dome.

How often does a solar eclipse happen on the March equinox?

Composite total solar eclipse Aug. 1999 by Fred Espenak.

A total solar eclipse is nature’s grandest spectacle. This composite image is by eclipse master Fred Espenak.

There’s a total solar eclipse coming up at this month’s equinox. When is the next one after this, and how often do we get an equinox-eclipse?

What makes a halo around the sun or moon?

A moon halo in Mandan, North Dakota by Marshall Lipp. February, 2015.

A moon halo in Mandan, North Dakota by Marshall Lipp. February, 2015.

Your Friday FAQ! Here’s what causes those rings of light around the sun or moon … plus lots of cool photos.