November morning sky at Old Scituate Light in Scituate, MA USA.
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.
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.
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.
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.
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.
Bottlenose dolphins in Africa use signature whistles to identify each other, similar to the way humans use names, say scientists.
You’ll see the Small Magellanic Cloud from Earth’s Southern Hemisphere. It’s even farther to the south than its larger cousin, the the Large Magellanic Cloud . These two hazy patches in the southern sky are really separate galaxies from our Milky Way. They are satellite galaxies to the Milky Way, orbiting around it. Follow the links inside to learn more about the Small Magellanic Cloud.
The star Omicron Ceti – aka Mira – in the constellation Cetus varies in brightness like clockwork over 11 months. That’s why, for centuries, stargazers have called it Mira the Wonderful.
Ah, Thanksgiving Day. You pile your plates with turkey, dressing, two kinds of potatoes, cranberries – all the traditional foods – and dig in. Second helpings? Of course! An hour later, after plenty of food and conversation, you push back and notice you’ve become very, very sleepy. You think, “I’m sleepy because turkey is high in tryptophan.”