September 24th, 2008 by David
What is a sunspot? It’s not the freckle on your nose. But, it is like a freckle on the sun. When astronomers look at the sun through special filters, they can see it better since it is less bright and they can look at light we can’t see (like ultraviolet light). Yesterday, a new sun spot showed up (see picture).
A sunspot is a part of the sun surface that has a lower temperature than the surrounding area. It also has a lot of magnetic activity. Some people believe that sun spots can affect the weather on Earth, including global warming.
Sun spots come in cycles that last several years. This particular sun spot is unique because it is believed to be the first in a new cycle called Cycle 24. (Scientists are not very creative at coming up with names for some things).
August 6th, 2008 by David
Commercial space travel is our best bet for getting into space sooner.
There was an episode of Star Trek the Next Generation where Captain Picard makes first contact with a species that had just developed warp drive. Due to social immaturities in their culture, their visit was kept a secret and space travel for that planet was postponed until they could take care of themselves.
We face a similar situation. A significant proportion of our world population earns less than $1 a day, goes hungry, is uneducated, and is infected with preventable disease like HIV/AIDS and malaria. How can we ethically spend billions on space travel, when we can’t take care of our own?
The answer is commercial space travel. Once the Fortune 500 figure out a way to make money in outer space, capitalistic efficiency will drive technology to make it much cheaper and easier to travel in space. I’m the worlds biggest space travel fan, but I don’t think it should happen at the expense of millions of starving children.
June 28th, 2008 by David
At Orbit!, the 3D online planetarium, you can fly in orbit around the Earth, view the stars, travel in time, find the planets, see what Earth looks like from the Moon, see the far side of the moon and much more. You can see constellations, dial in specific star coordinates and see the sky divided into constellation boundaries. The milky was is available in two optical intensities as well as infrared and atomic hydrogen.
What even more incredible is that this online planetarium is celebrating it’s 10 year anniversary this summer. It’s hard to believe that cyber technology this good has been around for over a decade.
June 26th, 2008 by David
Star maps or star charts help us to find things in the sky. They are not the 3D-charts that would help starship captains to find a planet to land on, but they would point them in the right direction when they first leave Earth. They are a projection of celestial objects on a virtual sphere that our planet is inside of.
These maps break-up the sky into areas, similar to states or providences in a country that correspond to constellations. Stars within these areas are given names based on the Latin name for the constellation proceeded by a Greek letter. For example, Rigel is Beta Orionis (Orion), the north star Polaris is Alpha Ursae Minoris (Little Dipper) and Sirius the brightest star in the sky is Alpha Canis Majoris (Canis Major or the big dog).
To be even more precise there is a coordinate system similar to latitude and longitude. Right ascension, or Ra, is like longitude except the zero point is not the Prime Meridian, it is the Point of Aries, or where the sun is on the first day of spring. Ra is measured in hours going east of the Point of Aries. Declination, or dec, is like latitude, only in the sky. If you were on the equator and looked straight up, you would be looking at a declination of 0°. Straight up from the north pole is 90° and straight up from the south pole is -90°.
Sirius is at 06h 45m, -16°, Polaris is at 02h 32m, 89° (pretty close to 90° that’s why it’s called the North Star) and Rigel is at 05h 15m, -8° (close to the equator, which is why Orion can be seen in both the northern and southern hemispheres).
June 24th, 2008 by David
Stephen Hawking would probably say, “Scintillate, scintillate stellar body with a magnitude greater than one.” But, that would make for a lousy poem.
What makes stars twinkle? Twinkling is technically known as stellar scintillation. It is caused by atmospheric turbulence. One of the advantages the Hubble telescope has is not having to deal with twinkling, since it is outside of our atmosphere.
What makes stars little? How big or little a star looks in the sky is a factor of not only how big and bright a star really is, but also how far away it is. Astronomers measure the apparent brightness of stars using magnitudes. Unfortunately the scale is backwards. The smaller the magnitude, the brighter the star. (Go figure.)
The brightest stars are about -1. Stars can have magnitudes of -1, 0, 1, 2, 3, 4, and so on. The scale is logarithmic, kind of like the decibels your stereo puts out. Each star magnitude is 2.512 times brighter than the previous magnitude as you move down the scale. A magnitude of 1 for example would be 100 times brighter than a 6. A -1 would be 100 million times brighter than a 19.
June 16th, 2008 by David
There has been a lot of talk over the last few years about looking for water on the moon. Some feel that there could be a frozen lake in one of the polar craters that has never seen the light of day. What is the big deal? Do the astronauts want to go ice skating?
Hardly. The main reason is that water can be turned into fuel. Most of the cost of sending things into deep space is fuel. It costs tens of thousands of dollars per pound to launch a rocket and most of the weight is fuel. If a rocket could refuel on the moon, it would make deep space exploration less expensive.
June 9th, 2008 by David
Orion the Hunter is a familiar winter friend. When I lived in South America for two years, this was the one constellation I could see that I recognized from the northern hemisphere.
Orion has two very famous stars, Betelgeuse (right shoulder) a giant red star and Rigel (left knee) a huge blue-white star. The lesser known Bellatrix (left shoulder) is a name made famous thanks to the Harry Potter books. The Orion Nebula can be found in the middle of Orion’s sword.
According to mythology, Orion was a giant hunter who challenged the gods by claiming to be able to kill every wild beast in the world. They sent a giant scorpion that killed him. After his death, the gods raised both of them to the heavens as constellations.
June 3rd, 2008 by David
A light year is the distance light travels in a year, or about 6 trillion miles. The space shuttle traveling at top speed (17,000 mph) would take about 40,000 years to travel one light year. To put things in perspective, the closest star is 4.3 light years away. Now that’s some serious elbow room!
May 7th, 2008 by David
Spatial diversification may be what saves the human race. We have literally placed all our eggs in one basket, the planet earth. One planetary catastrophe like a rogue comet, a viral mutation, a nuclear winter or melting polar ice caps could place our species at risk.
Colonizing the moon, Mars, or other heavenly bodies is like backing up files on a hard drive. You hope you never have to use the backup, but if your hard drive crashes, you’re glad you did. If you think I’m kidding, just ask the next dinosaur you see.