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A famous variable star in the constellation Cepheus

The constellations Cepheus the King and Cassiopeia the Queen sit high in the northern sky on November and December evenings. Once you find Cepheus, you can locate Delta Cephei, a famous variable star. With clock-like precision, this faint star doubles in brightness every 5.36 days.

NASA is tracking a gargantuan iceberg, escaped from Antarctica

Earth Observatory's first look (above) at B31 following the Southern Hemisphere winter was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite on November 22, 2014.

A first look at Antarctic iceberg B31, following the Southern Hemisphere winter. NASA’s Aqua satellite captured this image on November 22, 2014.

Winter has lifted from Antarctica’s Pine Island Bay, so that passing satellites can once again acquire sunlit views of massive iceberg B31 as it drifts in the Amundsen Sea. NASA has been tracking this iceberg – an ice island, really – since it separated from the front of Antarctica’s Pine Island Glacier a year ago (November 2013). It was thought it would likely be swept up in the swift currents of the Southern Ocean, but, for now, it’s still in the Amundsen Sea – moving west – free now of surrounding debris and sea ice.

Video: Astrophysicists discuss the film Interstellar

A fun Google+ hangout on the science of the blockbuster film “Interstellar.” Three astrophysicists answered viewers’ questions about black holes, worm holes, exoplanets, time dilation, and more, separating the movie’s science facts from its science fiction. It’s fascinating stuff. Enjoy!

Neptune near moon on November 28

2014-nov-28-aquarius-neptune-sigma-aquarii-moon-night-sky-chart

Neptune, the eighth planet out from the sun and outermost of the major planets according to the International Astronomical Union, is the only major planet in our solar system that you absolutely can’t see with the unaided eye. It’s near the moon on the night of November 28, but because of the moonlit glare, you won’t see Neptune very well, even if you have a telescope. What will you see? Only the moon shining in all its splendor. You can gaze at it and imagine Neptune nearby.

Although the moon and Neptune are close together on the sky’s dome tonight, they’re nowhere close in space. The moon resides about 1.2 light-seconds from Earth, whereas Neptune looms way out there at over four light-hours away. In other words, Neptune is over 12,000 times farther away than the moon in tonight’s sky.

Good morning!

November morning sky at Old Scituate Light in Scituate, MA USA.

Is it true that Jupiter protects Earth?

Brown spots mark the places where fragments of Comet Shoemaker-Levy 9 tore through Jupiter's atmosphere in July 1994.  Image and caption via Wikimedia Commons.

Brown spots mark the places where fragments of Comet Shoemaker-Levy 9 tore through Jupiter’s atmosphere in July 1994.

Here’s a question we get regularly:

Is it true that Jupiter could be considered our friendliest planet because – without Jupiter – comets would be more likely to hit us?

The answer is yes … and no.

Using supermassive black holes to measure cosmic distances

“Eye of Sauron,” an actively growing supermassive black hole at the center of the galaxy called NGC 4151.

How do we know the distances across space? Astronomers start with an actual measurement of nearby stars via stellar parallax and use a stepping stone method to estimate the vast distances beyond the closest stars. It’s impressive, but the method is full of guesstimates, and thus cosmic distances are known to be uncertain. Now researchers from the Niels Bohr Institute at the University of Copenhagen say they’ve demonstrated that precise distances can be measured using supermassive black holes.

Earth has its own Star-Trek-like invisible shield

Scientists have discovered an invisible shield roughly 7,200 miles above Earth that blocks so-called “killer electrons,” which can fry satellites and degrade space systems during intense solar storms. Illustration by Andy Kale, University of Alberta.

Scientists have discovered an invisible shield roughly 7,200 miles (11,600 km) above Earth that blocks so-called “killer electrons,” which can fry satellites and degrade space systems during intense solar storms. Illustration by Andy Kale, University of Alberta.

Today, scientists announced an “extremely sharp” boundary at the inner edge of the outer Van Allen radiation belt. They say this boundary layer is Earth’s own invisible Star-Trek-like shield, in that it appears to block ultrafast electrons from moving deeper into Earth’s atmosphere.

Animation shows Venus in evening sky late 2014 and 2015

Larry Koehn of the wonderful website shadowandsubstance.com dropped us a note today about his newest astronomy animation. It shows the much-anticipated upcoming apparition of the sky’s brightest planet – Venus – in the evening sky in late 2014 and 2015.

Dolphins use specific whistles as names

Image credit: Shutterstock / Willyam Bradberry

Image credit: Shutterstock / Willyam Bradberry

Bottlenose dolphins in Africa use signature whistles to identify each other, similar to the way humans use names, say scientists.