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FAQs

What is a coronal mass ejection or CME?

Aug 2012 CME

Aug 2012 CME

Every so often, the sun burps with the power of 20 million nuclear bombs.  These hiccups are known as coronal mass ejections (CMEs)—powerful eruptions near the surface of the sun driven by kinks in the solar magnetic field.  The resulting shocks ripple through the solar system and can interrupt satellites and power grids on Earth. During a CME, enormous bubbles of superheated gas—called plasma—are ejected from the sun.  Over the course of several hours, one billion tons of material are lifted off the sun’s surface and accelerated to speeds of one million miles per hour.  This can happen several times a day when the sun is most active.

Does the North Star ever move?

Sky wheeling around Polaris, the North Star.

Sky wheeling around Polaris, the North Star.

Polaris – the North Star – is like the hub of a wheel. It doesn’t rise or set – instead, it appears to stay put in the northern sky.

Scared of thunder and lightning? You have astraphobia

Never let your pets watch scary movies. Never a good idea! Image Credit: John Veldboom via Flickr

Thunder and lightning can be scary to pets, too. Image via John Veldboom via Flickr

Bam! Yikes!

Do you – and your dog – have astraphobia?

I saw a flash in the night sky. What is it?

Nature & Man: Iridium Flare, Milky Way, Clouds and Light Pollution by Mike Taylor.  Visit Mike Taylor Photography.

Iridium flare by Mike Taylor Photography.

Many people ask us about flashes in the night sky. They see one and want to know, what is it? Unless one of us were standing there next to you, we have no way of knowing exactly what you saw. So we can’t say for certain. But it’s possible that what you saw is a flare from an iridium communications satellite.

Dates of sun’s entry into each constellation of the Zodiac

The ecliptic passes through the constellation Taurus the Bull, to the north of the star Aldebaran and to the south of the Pleiades stars cluster.

The ecliptic passes through the constellation Taurus the Bull, to the north of the star Aldebaran and to the south of the Pleiades stars cluster.

On May 14, 2015, the sun enters the constellation Taurus the Bull. Dates of sun’s entry into each zodiacal constellation and the corresponding ecliptic longitude (sun’s position in degrees, east of the March equinox point), inside.

What is a dwarf planet?

You’ll know in 60 seconds. New Space Shorts video from NASA

What makes a red rainbow?

Göran Strand of Sweden captured this double red rainbow.  Used with permission.

Photo by Göran Strand. Used with permission.

Astrophotographer Göran Strand of Sweden kindly gave us permission to publish this photo, which a phenomenal double red rainbow. Details … inside.

How far is a light-year?

The Orion Nebula, 1,500 light years from Earth. Image credit: NASA/JPL-Caltech/STScI

The Orion Nebula, 1,500 light years from Earth. Image credit: NASA/JPL-Caltech/STScI


Here’s your FAQ for this Friday ….

Light is the fastest-moving stuff in the universe. It travels at an incredible 300,000 kilometers (186,000 miles) per second. That’s very fast. A light-year is the distance light travels in one year. How far is that?

What is the sun’s proper name?

Our sun.  By any other name, it'd still be awesome.  Image via NASA.

Our sun. By any other name, it’d still be awesome. Image via NASA.

You’ve no doubt heard some star names such as Polaris the North Star – or Betelgeuse in the constellation Orion. But, although it’s also a star, our sun doesn’t have a generally accepted and unique proper name in the English language. Most of us just call it the sun.

Why do we celebrate May Day?

Happy May Day!

May Day is an ancient spring festival in the Northern Hemisphere. It’s an astronomical holiday, one of the year’s four cross-quarter days, or day that falls more or less midway between an equinox and solstice.