Dr. Bortrum
07/31/2010
Stars and Whales
I ended last month's column saying that I was finding it hard to write about scientific subjects in the summer heat and I threatened instead to begin to write my memoirs. In the spirit of recalling memories for such a project, I spent far too much time watching the British Open at St. Andrews, with my score card in hand from the time my wife and I played there on September 10,1985. In awe of the coolness with which Oosthuisen managed the final round, I savored my own finishing the last three holes in darkness, finding my way by the light of the moon and the lights of the hotel and shops bordering the last two holes. There was no way I was not going to play that most famous of par 4s, the 17th road hole. For those of you who are golfers, I carded a 12, 8 over par, on the hole. I managed to hit the shed (I heard the ball hit something and assume it was the shed) over which the pros drive and couldn't find my ball in the darkness. Yes, I counted that as a stroke.
Something else I saw on TV brought back memories. I was quite surprised to see that former presidential candidate George McGovern celebrated his 88th birthday by skydiving out of a plane in Florida recently. I hadn't remembered that he was a World War II combat pilot in the Army Air Corps. Seeing his jump brought to mind one of the times that our editor Brian Trumbore was visiting on Marco Island. On February 18, 2004 my wife and I drove Brian to see where George McGovern was living, across the street from the couple who owned the condo we were renting on Marco. It happened that George was out walking his dog and we stopped to chat with him briefly. He allowed as to how the forthcoming Bush - Kerry election that year would be a "horse race". Although not as maddeningly close as the 2000 election, the 2004 election did fit the "horse race" category, with Ohio's 20 electoral votes finally putting Bush in the White House for a second term.
I was going to continue in a memory-related theme but then I became aware of a number of recent findings that changed my mind, being a sucker for anything related to astronomy or outer space. One item, published in the Monthly Notices of the Royal Astronomical Society (RAS), concerns the discovery of the most massive star found to date. The researchers. led by led by Paul Crowther at the University of Sheffield in England, used the European Southern Observatory's Very Large Telescope in Chile, as well as archives from the Hubble space telescope. I should note that the Very Large Telescope is really four large telescopes coordinated to collect and mesh the light from distant objects to give "exquisite resolving power", as a press release on the RAS Web site puts it.
The most massive star found to date is now 265 times as massive as our Sun. When this star was born about a million years ago it was over 300 times as massive as our Sun. Heretofore it seems that the most massive stars were in the 150 times-as-massive range. A star that's born 300 times a solar mass isn't long for this world. Such a big star burns itself out in only a couple of million years and its fate appears to be in question. Stars significantly bigger than our Sun generally explode to form a supernova and end up as black holes or neutron stars. Will this massive star end up the same way or will it just blow itself up to smithereens? We'll never know.
Another star made the headlines this month. On occasion, we've touched on the dangers of comets, asteroids or other chunks of matter wandering through our solar system and possibly striking the Earth a devastating blow similar to the one that led to the dinosaur extinction. But what about a runaway star? A NASA release on July 22 tells of just such a star, which fortunately is well outside our Milky Way and headed farther away at a speed of 1.6 million miles per hour! That's three times faster than our Sun is orbiting the center of our Milky Way galaxy. Based on observations from the Hubble Space Telescope over a period of years, the path of the star indicates that it came from the center of our galaxy.
The star is about 9 times more massive than our Sun and is a blue color; it's called a "blue straggler". It is also some 200 thousand light-years above our Milky Way disc, which is roughly a hundred thousand light-years in diameter. This presents a problem. To have gotten where it is, the star must be 100 million years old. The problem is that a star of this size and color should have burned out after only 20 million years! NASA explains this conundrum by proposing the following scenario. Initially, three stars were coupled (tripled, actually) together and were travelling together near the center of our galaxy. They traveled too close to the black hole in our galaxy center and the black hole gobbled up one of them. The remaining pair of the trio recoiled and were ejected from the Milky Way's center and eventually left the galaxy. Somewhere along the line, the two stars merged to form the blue straggler we see today. This straggler joins some 16 other stragglers, all discovered since 2005. Apparently, none of the other stragglers has been tracked down to its source.
I had planned to finish this column with another space topic but have just finished reading the August issue of National Geographic and couldn't resist telling you about a stunning example of fossils that provide key links in the evolution of a most remarkable species, the modern whale. The article, "Valley of the Whales" by Tom Mueller, tells of the work of Philip Gingerich and others in a most unlikely place to be studying whale evolution - the Wadi Hitan, an Egyptian desert! Now I know that you may have read of marine fossils being found in unlikely places such as mountain tops but I certainly would not have expected that an African desert would be the site where to date the remains of more than a thousand whales have been found!
Perhaps you have not heard of the Tethys Ocean? I hadn't and was shocked to find my spellchecker knew the word Tethys. Turns out Tethys was the daughter of Uranus and wife of Oceanus in Greek mythology. Some 37 million years ago there was an ocean, the Tethys, which extended all the way from Gibraltar over to India. Much of what is now Egypt and other parts of Africa and Asia were under water. About 34 million years ago a very hefty cooling period set in and the seas receded, sediment built up and deserts were formed covering up the fossils of those creatures that died in the Tethys Ocean, which died out, becoming the Mediterranean sea and the Indian Ocean. As time went on the windblown Wadi Hitan desert's sands were blown off, exposing the rocks that had formed around the marine fossils. There's a picture in the Geographic article of the Wadi Hitan desert, with many big rocks, some actually looking like whales and presumably some indeed still contain whale fossils.
Whale fossils per se would not necessarily be all that interesting, except for one thing. These were not your modern whales but early whales, whose ancestors had taken the first steps back into the water and increasingly found that environment to be to their liking. Of course, the distant ancestors of those ancestors had come out of the water to live on land. We've talked before about how whales are actually land mammals that decided the sea was a more lucrative place to feed and live than the land. I think we also mentioned how the whale's closest living relative is now thought to be the hippopotamus. We've discussed fossils of fish-like critters that had precursors of legs and provided a link in the sea-to-land movement. Now, in the Wadi Hitan, Gingerich and others have found fossils of all sorts of marine life such as giant catfish and those thousand or so whales, one being a true gem of a fossil, those of Basilosaurus. Basilosaurus was about 50 feet long and was indeed a whale that swam around in the Tethys before the cooling started 34 million years ago.
Why were Gingerich and his fellow researchers ecstatic when they had fully examined Basilosaurus fossils? Way back in this creature's tail, where one would expect a couple of small flippers, they found delicate hind legs about the size of the legs of a young child! Obviously of no possible value for walking, the Basilosaurus legs had not yet evolved into more useful flippers for living in the aqueous environment. The scientists speculate that perhaps Basilosaurus hung on to vestiges of legs for so long because they may have been useful in positioning the whale's bodies during sex. If so, with the cooling period setting in 34 million years ago, the legs began disappearing and the modern whale was making its debut, with all sorts of features such as shape of the head, brain size, insulating blubber and others coming into play.
In the years that the researchers have been studying the fossils of the Wadi Hitan, other earlier fossils have been found of animals that were just beginning to spend more and more time in the water and in deeper and deeper water. Legs were still useful to walk along the bottom of shallower bodies of water and were needed to come back onto and walk on the land. I've only skimmed some of the most salient points of the Geographic article and highly recommend you read the article if you're interested how the whale, once thought by skeptics of evolution to be one of the biggest thorns in the side Darwin's theory, is now one of the most convincing examples confirming evolution.
Next month I may or may not be here with a memoir. Whatever, I hope to have something new posted on or before September 1. Enjoy the rest of the summer.
Allen F. Bortrum
