by Kim Malville
This month’s sky
June 1-13: About 45 minutes after sunset look to the northwest for Mercury and Venus. This will be the best opportunity to view Mercury this year, which will be above the brighter Venus. Mercury will be highest in the sky on June 6 and 7. A few days later, on June 10 and 11, the new crescent moon will move past them. Look upward to see Castor and Pollux of Gemini, the Twins.
June 17: The moon will be to the right of Spica
June 18: The moon will have moved between Spica and Saturn
June 19: The moon lies between Saturn and the brightest star of Libra, Zubenelgenubi.
June 20: Summer solstice 11:04pm MST. The shortest night of the year.
June 23: The largest full moon of the year rises around sunset.
Comet of the century?
The possible “comet of the century” is hurtling toward a rendezvous with the sun in November, currently at a speed of 47,000mph. The Hubble Space Telescope photographed it for the first time on April 10. At that time the comet was 386 million miles from the sun. Even at that great distance, the sun was warming the comet’s surface, causing it to release gases and dust from its icy nucleus, which is relatively small 3 or 4 miles across, perhaps a quarter the size of Halley’s Comet. If the comet survives its close approach with the sun in late November, it could be a stunning sight, as bright as the moon with a huge tail. No promises however; its close approach to the sun may cause much of its ice to evaporate, leaving us with a dead comet head.
Explosion on the Moon
For the past 8 years, NASA astronomers have been monitoring the Moon for signs of explosions caused by meteoroids hitting the lunar surface. Lunar meteor showers have turned out to be very common, with hundreds of detectable impacts occurring every year. On March 17, the biggest explosion in the history of the program was detected. A small boulder, perhaps 12” across, hit the lunar surface with a speed of 56,000 miles per hour and produced an explosion equal to 5 tons of TNT. That’s a lot of TNT, but small compared to the 60’ diameter meteor that passed over Russia last February. It exploded in the air, producing an explosion equivalent to 440 kilotons of TNT, damaging 7200 buildings beneath its path.
Living on Mars
If NASA is to land humans on Mars by the 2030s, as President Barack Obama has directed, there’s not much time to settle on a plan and develop the technologies required. In the 1960s, America seized the opportunity to go to the Moon, and we succeeded. A second opportunity for a leap forward in space awaits us now. Sending people to Mars and getting them back is far more complex and expensive than Moon landings. The program will require at least three interdependent missions: (one) launch the crew and the vehicle that will take them to Mars, (two) launch the habitat the crew will live in to the planet’s surface, and (three) launch the vehicle that will lift off from Mars to take the crew home.
Some 200 to 400 metric tons of equipment will have to be launched from Earth’s surface for the project, and 40 metric tons of that will have to be delivered to the surface of Mars at one time. So far, NASA has been able to land only 1 metric ton at a time, recently accomplished when Curiosity landed on Mars last summer.
Hopefully those who land on Mars will be able take advantage of some of its resources such as water and oxygen for breathing, drinking and other needs. Not the least problem is that there must be a means of shielding astronauts from the dangerous radiation produced by solar flares, both during the journey to the Red Planet and on the Martian surface, which lacks a strong enough atmosphere to protect from these damaging particles. A rover would be sent to the landing site first, to drill a couple meters down to locate fresh water (good luck), and serve as a beacon to guide the crew down. It will be a great adventure but an expensive one. An alternate adventure is to become a scientist and explore the Antarctic.
Junk in space
Besides dodging the radiation from flares, the Martian astronauts will need to dodge space junk. NASA estimates there are more than 21,000 pieces of space junk larger than 4” in diameter orbiting the earth, some 500,000 smaller particles down to half an inch, and another 100 million tinier fragments. There is growing fear that this debris is approaching a tipping point, a threshold for collisional cascade, producing billions and billions more small objects. Once that threshold has been crossed, space will become even more dangerous. Today, hundreds of near-misses occur each year between orbital debris and operational satellites. NASA scientists have proposed to inject some 40 tons of titanium dust into this realm of orbiting junk, moving in opposite direction, which would collide with the debris, slow it down, and cause it to plunge to earth. Most of the dust as well as the small orbital debris will incinerate while reentering the Earth’s dense atmosphere. The larger pieces will eventually be slowed down and drift down to earth. Seventy percent will fall into the ocean. Astronomers hate the idea since it will increase the sky brightness. People who fear the falling sky should be petrified. Somehow, we need to clear the skies. What mischief we humans have wrecked upon this warming planet of ours! Hopefully we’ll do better with Mars, if and when we get there.