Aurora Watch for Salt Lake City (and other magnetic latitudes above 45N)
20% chance of an aurora visible tonight. Look to the north from a dark location!
September 4th, 2010
Waning Crescent Moon
Astrophysics
Posted by: Rob Morris
August 4th, 2010
August 4th, 2010
Posted by: Jesse Warner
June 16th, 2010
June 16th, 2010
Illusions of the seasons: Part 1
Understanding why the Earth has seasons is one of the most difficult concepts for people to understand because it is often difficult for people to abandon their preconceived ideas. Some widely held misconceptions are:
Misconception #1
The Seasons are caused by the changing distance between Earth and the Sun.
Misconception #2
There are two days in the [...]
Posted by: Robert Bigelow
May 16th, 2010
May 16th, 2010
Is the Sun directly overhead?
In my March missive on Daylight Saving Time, I mentioned a misconception that is held by some students and possibly some adults as well. A more common misconception concerns the apparent height of the Sun in the sky. When I ask students the question, “When is the Sun directly overhead in Utah?,” most students answer, “every [...]
Posted by: Robert Bigelow
April 26th, 2010
April 26th, 2010
Neutrinos and Supernova 1987A
Twenty-three years ago, on 23 February 1987 at 12:35 a.m. MST, detectors in the US, Japan and Russia observed a burst of 24 neutrinos. They came from a supernova in the Large Magellanic Cloud, a small satellite galaxy to the Milky Way. About 2 hours later, an experienced New Zealand amateur astronomer observed the area [...]
Posted by: Robert Bigelow
March 16th, 2010
March 16th, 2010
A Different Star
If we could travel back in time several thousand years to observe the night sky, we would notice two main differences compared to the night skies of today.
The most obvious would be the lack of a sky glow produced by a myriad of outdoor lights. This glow washes out the richness and beauty of [...]
Posted by: Robert Bigelow
January 11th, 2010
January 11th, 2010
“Mister” Sol’s neighborhood
The New Horizons spacecraft is on its way to Pluto. It left Earth back in January 2006. Now it is almost halfway between the orbits of Saturn and Uranus. When will it reach Pluto? Not until July 2015. Why so long? Pluto is “out there.” How “out there” is it? A scale model can help.
Posted by: Seth Jarvis
October 19th, 2009
October 19th, 2009
Planets Galore!
There’s an AP news story out today about astronomers announcing the discovery of 32 new planets orbiting stars other than our Sun. That’s quite a number for a single announcement!
I keep a little dashboard widget from NASA on my Mac at home that keeps a running score on the number of extra-solar planets that have [...]
Posted by: Seth Jarvis
August 18th, 2009
August 18th, 2009
Why are planets spherical?
Anthony Garcia wrote in to ask, “Why are planets perfect spheres, or at least appear to be perfect?”
Nature loves spheres. It can’t get enough of them.
Posted by: Seth Jarvis
July 31st, 2009
July 31st, 2009
Cosmic Quiz Winner
This week’s cosmic quiz question was submitted by Daniel Wallace, who asked, “How do astronomers figure out the size of planets orbiting other stars (and even what their atmosphere is made of)?”
Posted by: eric
July 22nd, 2009
July 22nd, 2009
How Big? A look at figuring size and scale
A few days ago, I needed to increase the size of an astronomical table to make it easier for my aging eyes to read. It was about half the size of a standard sheet of paper, so I decided to double its size. What scale setting should I use on the copier, 200%? Having been [...]