Old moon?: The moon cooled to a solid 4.4 billion years ago.
Courtesy ViaMoi
Where did the moon come from?
Scientific studies indicate the solar system formed about 4.6 billion years ago and that about 4.5 billion years ago an object about the size of Mars hit the Earth, blasting away material that eventually cooled into what is now our moon. (Read more in Science News: "The Solar sytem's big bang")
How do we know the moon's age?
Rocks brought back from the moon contain zircon crystals. Zircons crystallize only after 80 to 85 percent of a volume of molten rock has solidified. By understanding how uranium within the zirconium breaks down into lead, scientists believe they know when the crystals formed with an error margin of less than 4 million years. The oldest zircons from the moon are about 10 million years older than the oldest yet discovered on Earth. The ages of lunar zircons identified in other studies hint that small amounts of the moon’s crust remained molten for another 200 million to 400 million years.
"Alexander Nemchin and his colleagues have used a uranium-lead dating technique to scrutinize a 0.5-millimeter-wide zircon embedded in a moon rock collected by Apollo 17 astronauts in December 1972. The crystal — which, although small, is rather large as zircons go — is about 4.417 billion years old, the researchers report online January 25 in Nature Geoscience."
Source:
Science News: "Oldest zircon fine-tunes history of moon's formation"
Tags : 
Al & the Earth: I wonder if Al Gore runs a distributed computing program on his Mac when he gives his global warming talks. Probably not. Image courtesy alexdecarvalho via Creative Commons/Flickr.If you like science and you listen to podcasts I recommend Scientific American’s 60 Second Science. I don’t listen to them every day, but I store them up then listen to a bunch in a row while I am doing something menial. Today I listened to a bunch walking from my cube to the loading dock. It is a looooog walk.
Besides mentioning the giant Mars hoax emails, which I guess are circulating again with new dates, there were two stories caught my interest.
The first was about distributed computing. While I am an advocate for turning off computers at night to save energy, if you’re going to leave them on, you should put them to good use. They can either run scans on themselves, or, through distributed computing, they can use their processing power to solve large problems. One new distributed computing application that they mentioned that I found interesting is Cosmology@Home. Cosmology@Home uses your computer’s spare processing power to “search for the model that best describes our Universe and to find the range of models that agree with the available astronomical and particle physics data” (from their website). Since I can barely wrap my mind around the implications of that question I am glad that my computer can help find some answers.
Another interesting podcast was about global warming. Researchers from the University of Washington have been working on equations that will help get the most out of climate models. The result of their work is that while the Earth is going to get warmer, how much warmer is not known. Scientists have theorized that if the amount of carbon dioxide (CO2)in the atmosphere doubles the temperature would rise by about 2.2 degrees Fahrenheit. But, that rise in temperature does not account for the sort of “compound interest” that would take place – if the Earth warmed up because of more CO2, would the warmer atmosphere hold more water vapor? Would that increased amount of water vapor, serving as a “greenhouse gas” create even warmer temperatures? And what effect would these even warmer temperatures have on the climate models? This new equation helps scientists see the most probable scenarios more quickly than before, but also shows possible warmer results than previous models. The problem is that all this “compounding interest” makes it impossible to determine with any accuracy the high end possibilities. More on this can be found here, here and here.
Subscribe
I want to learn about
Science Buzz is supported by the National Science Foundation.Copyright © Science Museum of Minnesota, 2004-2010, except where noted.
Add a new comment