Dr. Bortrum
10/01/2014
Busy Time in Space
CHAPTER 49 Here on Earth and Elsewhere
Last month I wrote about raccoons and their ability to adapt to all sorts of environments. They did so well in Japan that there is a concerted effort to kill them off by the thousands because of the damage they have done to temples and other structures. Introduction of these Western hemisphere natives to Japan and also to Europe has not gone well. Following up on the critters, I saw an ad for Canon in the September 2014 issue of National Geographic on the White cay rock iguana. You've probably seen these Canon ads featuring endangered creatures. These iguanas live on the White (Sandy) Cay in the Bahamas and are now one of those endangered species, with only 1500 left. According to the ad, a single raccoon somehow got on the island and, before it died it had decimated the population of the iguanas. Raccoons don't just eat garbage!
I also mentioned last month that I had recently seen various wild creatures in our backyard including a fox, deer and rabbits. So far, no bears, although bears have been seen in nearby towns. In fact, this month a black bear killed a Rutgers University student hiking in a neighboring county preserve. Apparently, this was the first recorded fatal attack by a bear on a human here in New Jersey in over 150 years.
But enough about animals. Let's talk about what's happening on or above another world - Mars. NASA has been quite busy both on the surface and in the atmosphere above the Red Planet, as well as in the study of planets outside our solar system. On the surface of Mars, that intrepid rover Curiosity has just completed a long journey to the base of Mount Sharp. Curiosity landed on Mars two years ago in August 2012 and has now traveled some 9 kilometers, about 5 miles, and driving the intrepid rover has involved some changes in plans. The Curiosity team realized that the original planned path to Mt. Sharp involved relatively rough terrain with sharp stones that were damaging four of the six wheels on the rover. The path was changed to a less rocky route and the wheels have held up nicely so far.
Curiosity fulfilled its main mission early on with findings of evidence of water and other chemicals that could have supported life in the distant past history of Mars. Mt. Sharp is a layered structure that offers the opportunity to dig into that history and come up with more evidence as to what took place on Mars billions of years ago.
In addition to what's going on on the surface of Mars, there have been a couple of new arrivals up in the Martian atmosphere. Notably, India has joined the ranks of nations placing spacecraft on or around Mars. NASA Administrator Charles Bolden recently congratulated India on having successfully achieved orbit with its Mangalyaan spacecraft, which will study the atmosphere surrounding the planet. Just a few days earlier, NASA's own Mars orbiter, Maven, slipped into orbit. The two new orbiters make a total of three American, one European and the Indian spacecrafts orbiting Mars. One objective of the Maven orbiter is answer the question as to how and why Mars has been losing its atmosphere over the years. In particular, Maven will gather data as to how the Martian atmosphere reacts with the Sun and the solar wind. With such data one might extrapolate back in history to figure out when Mars likely lost its bulk of water that once existed on its surface.
On a different note, we here in New Jersey have been having some exceptionally good weather, sunny and warm, with clear skies, ideal for golfing and going to the beach. Naturally, I was intrigued to see that NASA had found clear skies on HAT-P-11b, a planet that orbits a star in the constellation Cygnus some 120 light-years from us here on Earth. Not only are the skies clear but the atmosphere of that planet contains water vapor. The finding and confirmation of the presence of water vapor required the combined use of the Hubble, Kepler and Spitzer space telescopes.
It's not an easy thing to do - finding water vapor on a planet way out beyond our solar system. The method used is to look at the light from the parent star as it passes through the atmosphere of the planet. First, the planet has to be in an orbit that crosses between the star and Earth. When this happens, if we're lucky, we can look at the light from the star as the light passes through the planet's atmosphere. If there's water vapor in the atmosphere it will absorb light at certain wavelengths and, by comparing the starlight without the planet in the way with the starlight through the planet's atmosphere, water vapor is detected. The Hubble telescope was used to make such measurements that indicated the presence of water vapor.
I would have thought that would be the clincher but, no, there's a possible complication. It seems that stars can have "starspots", like freckles on the surface. These starspots can be cool enough to produce water vapor, something I certainly was unaware of. It was at that point the NASA team turned to the Kepler and Spitzer telescopes. Kepler had been scanning the area of the sky containing HAT-P-11b for years and Spitzer's infrared measurements showed that any starspots on the planet's star were too hot to have been the source of any steam. Case closed - the water vapor is in the planet's atmosphere.
It would be great if the planet HAT-P-11b were an earth-sized planet orbiting in a habitable zone but no such luck. The planet is about the size of Neptune, which is roughly four times the diameter of Earth. It's apparently a gaseous planet, possibly with a rocky core, but not a place for life as we know it. Other, larger planets have been found to have water vapor but this latest finding is a another step towards the ultimate study of water and other molecules in the atmospheres of "super Earths", rocky planets with masses up to ten times that of Earth. Lots of these super Earths have already been found and, hopefully, we will soon find one with water and other molecules that suggest the possibility of life.
Finally, I didn't mention that our Maven spacecraft orbiting Mars will have an opportunity to take a peek at a comet. Comet Siding Spring will pass Mars only about 80 thousand miles away, about a third the distance between Earth and our moon. Maven happens to have just the sort of instrumentation suited to study this close passage of a comet, which occurs in just a couple of weeks from now, October 19. Indeed there was some concern that debris from the comet might damage Maven but it seems the likelihood of this happening is relatively small.
But the real comet story will hopefully take place next month on November 11, when the European Space Agency's Rosetta spacecraft will deploy its lander Philae down to the surface of the scraggly looking Comet 67P/Churyumov-Gerasimenko. Rosetta has approached to only about 20 miles above the comet's surface and a landing site has been selected. When Philae lands it will perform analyses of the composition and structure of the comet, which should reveal something about the history and evolution of the comet.
With all this activity going on in outer space it's certainly an exciting time for space enthusiasts like yours truly. Closer to Earth, it looks as though the United States is getting somewhat closer to once again not having to rely on Russia to ferry our astronauts to the International space Station, having awarded contracts to SpaceX and Boeing. If all goes well, we might once again be in shuttle-like mode in 2017.
Next column will be posted, hopefully, on or about November 1, 2014.
Allen F. Bortrum
