Archives for the 'Earth' Category
Vernal Equinox
Published on 20 Mar 2007 at 11:05 am.
9 Comments.
Filed under Earth, astronomy.
It happens in a few hours. At 00:07 UT, March 21, the Sun will be directly over the Earth’s equator. That time works out to be 7:07pm (CDT) on March 20 here in Texas. We call this the Vernal Equinox. The word “equinox” suggests equal times of day and night, and that […]
Mars isn’t the only planet with dust storms!
Published on 28 Feb 2007 at 1:45 pm.
No Comments.
Filed under Earth, Mars, space exploration.
Saturday, I was at a convention in Dallas. That afternoon, I came out of a session and looked out the window. During the day, the wind had been increasing. Well, by the afternoon, there were whitecaps in the hotel swimming pool! But, more disturbing was the fact that the Sun was […]
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The Future of the Moon
Published on 24 Jan 2007 at 5:06 pm.
3 Comments.
Filed under Earth, moon, physics.
A couple of days ago Space.com had an article that I read in newspapers all over the place. I won’t go into detail, you can read it. But, the summary is that the Moon is likely doomed. When the Sun swells up to be a red giant, the Earth-Moon system will be skimming along just […]
Sunrise, Sunset, and the Winter Solstice
Published on 17 Dec 2006 at 5:07 am.
16 Comments.
Filed under Earth, skywatching, time.
In a few days, it will the the Winter Solstice here in the northern hemisphere. The Sun will be the farthest south that it will get all year. That means that it will be the shortest day of the year for us. Now, for our friends in the southern hemisphere, it is […]
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Airglow
Published on 17 Nov 2006 at 2:11 pm.
5 Comments.
Filed under Earth, astronomy, atmosphere, skywatching.
Yesterday, I talked about twilight. I made it sound like once all the twilight was gone, then it got totally dark, with no light except that from the stars (moon, planets, streetlights, etc). Well, that isn’t quite true. As it turns out, it never gets completely dark. There is always some sky glow. And, that […]
The Aurora (Part 2: Origin of the Aurora)
Published on 12 Nov 2006 at 2:37 pm.
1 Comment.
Filed under Earth, aurora, physics.
Yesterday, I wrote about observing the aurora. Today, I am going to write a bit about the origin of the aurora. There are two types of aurorae: the diffuse aurora, which is shown above, and the disctrete aurora, as is shown to the right. The diffuse aurora is always present, but is very dim, lacks […]
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Duck, it’s 2006 QM111!
Published on 24 Sep 2006 at 1:45 pm.
6 Comments.
Filed under Earth, asteroids.
A week ago, I posted about a crater located here in Texas just west of Odessa. That crater was caused by something running into Earth. You can work out the mathematics of such an impact, and you find that the impacting body may have exploded with the equivalent force of 100 to 200 megatons of […]
