by Kim Malville
The brightest object in the sky this month will be Venus in the early morning hours. It is brilliant and unmistakable, looking like a brightly lighted UFO coming in for a landing. There are two planetary conjunctions this month. That is the good news. The bad news is that they are early in the morning before dawn. There is also a meteor shower, the Draconids, with the possibility of a few bright surprises.
October 3: In the east, at dawn, one hour before sunrise, Jupiter Mars, Regulus, and Venus will be in a straight line.
October 8/9: The Draconids coming out the head of Draco in the northern part of the sky. They are very slow moving meteors and can be seen in the evening once the sky is dark. There will be no interference by moon light. Some years this has been a spectacular shower. In 2011 it reached a maximum of 300 per hour. An hour before dawn of October 8, 9, or 10, look to the east to see the waning crescent moon among Jupiter, Mars, and Venus.
October 17 and 18: An hour before sunrise, Jupiter and Mars will come within half of a degree of each other. Jupiter dominates.
October 25 and 26: Venus moves close to Jupiter. This is the last of the recent series of conjunctions that resemble those in 3-2 BC, one of which may have been the so-called Star of Bethlehem. Venus will dominate Jupiter.
A really bad idea!
Mars is “a fixer-upper of a planet,” says Tesla and SpaceX CEO, Elon Musk. Mars is a pretty inhospitable place for us human to live at the moment, but it can be made more like the Earth. All it takes is the Mars equivalent of global warming but that takes time. If you’re in a hurry, he suggests, try nuclear bombs. The fast way, Musk has suggested, is to drop nuclear weapons over Mars’ poles. Musk says his rocket firm, Space Exploration Technologies, or SpaceX, will be capable of ferrying astronauts to the International Space Station in two or three years and perhaps to Mars in 10 years, and it would be so nice if they could land on a pleasant vacation spot.
There are two polar caps, which consist of 70% water ice and approximately 30% frozen carbon dioxide. The south cap has a permanent layer of dry ice that is about 25’ thick lying over water ice. The southern polar cap has a diameter of 350 km (220 mi) and a thickness of 3 km (1.9 mi). The total volume of water ice in the south polar cap is approximately 1.6 million cubic kilometers, about half the size of the Greenland ice sheet which contains 2.85 million cubic kilometers. Both polar caps have spiral troughs, which are a result of katabatic winds that flow downward and spiral due to the Coriolis Effect. Blasting these polar caps and vaporizing their ices in order to turn Mars into another Cozumel is a thoroughly bad idea.
New high-resolution images of Pluto are arriving every day from the outer Solar System. The robotic New Horizons spacecraft, which flew past Pluto in July, has finished sending back some needed engineering data and is now transmitting selections from its tremendous storehouse of images of Pluto and its moons. Traveling at the speed of light, signals take 4.5 hours to travel three billion miles to reach Earth, meaning the spacecraft has an enormous undertaking ahead of it. With data downlinking at a rate of approximately one to four kilobits per second, it’s expected the entire collection of pictures and measurements from the July 14 encounter will take one year to be transmitted back to Earth. The spacecraft, equipped with a battery that converts radiation from decaying plutonium into electricity, should have enough power for two more decades of exploration. Now the team is planning to cruse past another Kuiper belt object known as 2014 MU69 lying nearly a billion miles beyond Pluto. We will have a better name for that object soon enough.
With wide plains, high ice mountains and valleys, glaciers of frozen methane, dunes, and a multitude of other alien features, Pluto has emerged as a far more complicated planet than many astronomers and geologists expected. This dramatic image shows the ice plains of Sputnik Planum on the right, probably due to the bubbling up of underground methane and water. You can easily see glaciers at the edge of the Planum that are moving into the valley in the lower center. On the left are the mountains, topped by 11,000’ ice spires of the Norgay Montes. In the distance are the Hillary Montes. There is nothing like Pluto in our solar system. We have four rock planets in the inner solar system (Mercury, Venus, Earth, and Mars) and four gas giant planets in the outer solar system (Jupiter, Saturn, Uranus, and Neptune). Then there is Pluto, no longer classified as a full-fledged planet, demonstrating the power of human curiosity in exploring the unknown.
The bright spots of Ceres
Bright spots, blazing away like the eyeshines of cats, dogs, and other nocturnal creatures, were first detected by the robotic Dawn spacecraft as it approached Ceres in February of this year. These bright spots appeared most prominently in the center of a large crater, and throughout the succeeding months as Dawn got closer and closer, these spots grew stranger and stranger. Ceres is the largest object in the asteroid belt, which lies between the orbits of Mars and Jupiter. Its diameter is approximately 945 kilometers (587 miles), making it the largest of the minor planets, though half the size of Pluto, which has a radius of 1186 km.
Ceres appears to have a rocky core and icy mantle, and may have a regional ocean of liquid water under the layer of ice. Perhaps some of that water is emerging in the form of small cryovolcanos (ice volcanos), which erupts volatiles such as water, ammonia or methane, instead of molten rock. Collectively referred to as cryomagma or ice-volcanic melt, these substances are usually liquids and form plumes, but can also be vaporous. After eruption, cryomagma condenses to a solid form when exposed to the very low surrounding temperature. These small white dots may be miniature cryovolcanos, indicating the presence of a pool of water underneath. That raises some wonderful speculations about the possibility of primitive life in such a pool. We know about an ocean on Jupiter’s moon Europa, but that is very far away and moves through an intense radiation belt. Ceres is very accessible for exploration, by contrast.
Everyone expected that the puzzle would be solved when Dawn got closer and produced higher resolution images. However, even with the highest resolution photos yet, the riddle remains. Another recent clue is that a faint haze develops over the crater’s bright spots. Dawn is scheduled to continue to spiral down toward Ceres and scan the dwarf planet in several new ways that, it is hoped, will determine the chemical composition of the region and finally reveal the nature and history of the spots. In several years, after running out of power, Dawn will continue to orbit Ceres indefinitely, becoming an artificial satellite, left for future generations, millennia from now, to puzzle over.