by Kim Malville
What’s happening in the skies this month?
Jupiter dominates the skies this month. It is in retrograde in Gemini, moving slowly to the west. Try out some binoculars to view its brightest four inner moons, which nightly change their positions.
In the early evening the constellation of Orion will be due south. Look for the three stars of the Hunter’s belt. Above the belt to the left is the red giant Betelgeuse. On the lower right is the bright blue star Rigel. The belt stars align with the bright Dog Star Sirius. The Hunter is Greek. In Hindu mythology, this constellation is the father of humankind, Prajapati. The star Sirius is Rudra, the fierce form of the god Shiva. He has just shot an arrow into Prajapati, to prevent him from having intercourse with his daughter, Rohini, the bright red star that we know as Aldebaran, the red eye of Taurus the Bull. The arrow appears as the three stars in the body of Prajapati. These are two remarkably different stories!
February 1: Look to the western skies about 45 minutes after sunset. If you look carefully you will find Mercury below a thin sliver of the moon.
February 10: Jupiter is above and to the left of the moon.
Rosetta wakes up and calls home
As I write this column on 20 January 2014, the Rosetta Spacecraft awakened from two years of hibernation and called to us. The spacecraft, which carries a 220-pound lander called Philae, has been hibernating for most of the past three years to save power. It is due to reach its destination, the 2.4-mile diameter comet called 67P/Churyumov-Gerasimenko in August. The lander is named after the Nile island Philae where an obelisk was found that helped decipher the Rosetta Stone.
At a distance of 500 million miles from Earth and just inside of Jupiter’s orbit, radio transmissions, traveling at the speed of light, take 45 minutes to reach the earth. (Reminds me of a joke: When the airline flight attendant asked the photon if he had any bags to check, he said, “No, I’m travelin’ light.”).
Rosetta was put into hibernation in June 2011 when its path took it so far from the Sun that its solar panels would harvest minimal energy. Starting in four months Rosetta will begin firing its thrusters to begin zeroing in on the target comet. Today, the separation is nine million km. By mid-September, it will have been reduced to just 10km. The plan is for Rosetta to escort the comet for 17 months, as it moves closer towards the Sun, monitoring the changes that take place.
Comets are the pristine remains of the gas cloud that produced our solar system some 4.6 billion years ago. The mission should provide more clues about how the solar system came into existence, much like the Rosetta Stone, which provided a blueprint for deciphering ancient Egyptian hieroglyphs. Comets are giant ice blobs mostly covered by a dark tar-like substance. The oceans of the earth may have been formed by hundreds of thousands of comets hitting the earth some three billion years ago. These comets may have contained organic molecules, such as amino acids or even more complex molecules, which could have been the seeds for life on earth. These wonderful objects may thus have carried both water and life to the earth.
One of Rosetta’s first tasks will be to scout for a suitable landing location for its piggyback-riding Philae probe. It is outfitted with twin harpoons laced with tethers that will be fired into the comet’s surface to anchor Philae and keep it from bouncing back into space after touchdown.
Philae will drill into the comet and extract core which will be analyzed by organic chemistry experiments. Those results will be beamed up to Rosetta, which will in turn be transmitted to Earth.
The mystery rock on Mars
After 10 years of wheeling around Mars, NASA’s Opportunity rover has discovered a new rock shaped like a jelly doughnut that appeared out of thin Martian air.
In late December, Opportunity snapped an image of a rocky outcropping with no rock the size and shape of a jelly doughnut. But 12 days later, when the rover took another picture of the same area, the jelly doughnut-like rock was there. The Opportunity team has come up with two theories to explain the rock’s mysterious and sudden appearance. One idea is that Opportunity’s wheels somehow flicked the rock out of the ground and into field of view of Opportunity. The second theory is that the rock was thrown into place when a meteorite hit the planet some distance away. In any case, the brightness of the rock indicates that its surface is newly exposed to light and may reveal something intriguingly new.
The Opportunity team has just started to take a closer look at the rock to figure out its composition. So far, those results have been baffling. For example, they discovered that the red “jelly” part is very high in sulfur and magnesium, and that it has twice as much of the element manganese as anything they’ve ever seen on Mars. The Opportunity team reports that they are “completely confused”, and having a wonderful time, arguing amongst themselves. By the time you read this column ten days from now, perhaps the mystery will be solved.
A new supernova
One day after Rosetta called home, an exploding star was discovered by a group of students at the University College London. It is the closest supernova found in more than 30 years and should be a cornucopia of astronomical information. Almost as remarkable, it was discovered beneath the thick atmosphere of London. This kind of supernova is produced by white dwarf stars when they collide with each other or when a white dwarf become unstable because a neighboring star dumps too much gas on it. The supernova is in the galaxy M82, otherwise known as the Cigar Galaxy, about 12 million light-years away in the constellation Ursa Major, the Big Dipper. Instead of a delay of 45 minutes from Rosetta, there has been a delay of 12 million years for these photons to reach us. Come to think of it, light is not all that fast!