September 30, 2008 at 9:00 am | Leave a Comment
And Climate Change
Sometimes you can’t keep ahead of the news. Especially in science. As I was working on the climate change exhibits for California Academy of Sciences earlier this year, I’d keep tabs on research and discoveries in Earth sciences, particularly Earth’s atmosphere and oceans. And, as fast as I’d write up something from peer-reviewed science, there’d be more information and discoveries coming in. Which is great, but when it comes to climate change, it seems like it might be chronicling drastic change that we neither need nor want. But, that’s the nature of science research — it reports on what’s happening and tries to find out why it’s happening.If we’re smart, we heed what we see and take action.
Tomorrow there’s a peer-reviewed science paper coming out that I wish had come out earlier, since it would make a striking addition to the exhibits. It states that as Earth’s oceans absorb more carbon dioxide generated by human consumption of fossil fuels and other activities (which warms up oceans and causes them to become more acidic), sounds will travel farther underwater. What’s the big deal, you might ask. Well, noisier oceans affect marine mammal, for one thing. And, there are likely other effects that reverberate throughout the ocean environment.
This projected impact on ocean sound is the result of calculations by Keith Hester and his colleagues at the Monterey Bay Aquarium Research Institute (MBARI) in Moss Landing, Calif. Their paper is coming out in tomorrow’s (October 1, 2008) issue of Geophysical Research Letters, a journal of the American Geophysical Union (AGU).
So, what does it mean? Ocean chemists know that as seawater chemistry changes, its ability to absorb sound changes. As sound moves through seawater, it causes groups of atoms to vibrate, absorbing sounds at specific frequencies. This involves a variety of chemical interactions that are not completely understood.
The overall effect is strongly controlled by the acidity of the seawater. The bottom line is this: the more acidic the seawater, the less low- and mid-frequency sound it absorbs.
As the oceans become more acidic, sounds will travel farther underwater and the level of underwater noise will rise. This change in chemistry will have the greatest effect on sounds below about 3,000 cycles per second (two and one half octaves above “middle C” on a piano).
This range of sound includes many of the underwater noises generated by industrial and military activity, as well as by boats and ships. Such human-generated underwater noise has increased dramatically over the last 50 years, as human activities in the ocean have increased. For marine mammals that also use this range of sounds to communicate, it’s like having your neighborhood go from one of relative quiet to one where the neighbors are blasting their stereos and revving their engines all the time.
The MBARI researchers say that sound already may be traveling 10 percent farther in the oceans than it did a few hundred years ago. However, they predict that by the year 2050, under conservative projections of ocean acidification, sounds could travel as much as 70 percent farther in some ocean areas (particularly in the Atlantic Ocean). This could dramatically improve the ability of marine mammals to communicate over long distances, but, on the down side, it could also increase the amount of background noise that they have to live with.
There are no long-term records of sound absorption over large ocean areas. However, the researchers cite a study off the coast of California which showed an increase in ocean noise between 1960 and 2000 that was not directly attributable to known factors such as ocean winds or ships.
Hester’s research shows how human activities are affecting the Earth in far-reaching and unexpected ways. As the researchers put it in their paper, “The waters in the upper ocean are now undergoing an extraordinary transition in their fundamental chemical state at a rate not seen on Earth for millions of years, and the effects are being felt not only in biological impacts but also on basic geophysical properties, including ocean acoustics.”
September 29, 2008 at 13:15 pm | Leave a Comment
Control System Failure Cuts Off Science
and May Affect Servicing Mission
Well this is bad news. NASA Spaceflight.com is reporting that science operations on Hubble Space Telescope have been shut down by the failure of the “Side A” control system. The telescope is in safe mode but is without any way to run the science instruments. HST’s technical handlers are working to transfer control of science operations to a Side B backup system, but this will take some time. Side B has never been used on orbit, but is assumed to be in working condition. If it works, then science can resume.
However, from what I’m able to glean from several websites, this may affect the servicing mission scheduled for an October 14 launch. If Side B can be activated and used, then the mission may well go on as scheduled. If Side B is not working, the mission could be delayed into 2009 in order to figure out a repair strategy. This is still a developing situation, so stay tuned.
Update: the upcoming repair mission for HST has been delayed until 2009, and the telescope’s handlers will work to bring up Side B to use until the astronauts have been trained on replacing the parts for Side A (and those parts can be put together). For an in-depth look at the issues, check out Phil Plait’s Bad Astronomy Blog.
In other news: I was on travel last week and didn’t get a chance to blog about the Chinese space mission until now. I think it’s very cool and wish their agency the best of luck! In a way it was like watching the U.S.’s own first steps in space in the late 50s and early 60s. Congrats to the Chinese taikonauts!
September 29, 2008 at 8:15 am | Leave a Comment
It’s pretty common knowledge in planetary science circles that rocks blasted off of Mars by impacts and collisions have been landing on Earth as Martian meteorites. These rocks have been found in various places on our planet (deserts, the Antarctic), and chemical analyses prove that they came from Mars. (If you want to know more about how and why we know this, read here and here.)
The thing is, these rocks deliver timely information about conditions on Mars at the time they were blasted away. The mineral content tells us about what elements existed in the crust of Mars and the conditions that created and modified the surface rocks. So, you can think of Martian meteorites as snapshots of the Mars-that-was.
Not only could those rocks carry Mars-made minerals to Earth, but under certain conditions, they might be able to carry traces of life here as well. That very possibility has been a lively topic of research ever since the first rocks from Mars were identified as such.
Now, to be sure, life traces are delicate things, and they might not survive the trip through space and then the essentially hot, violent and shock-filled entry into our thick atmosphere. But, if such traces COULD survive, scientists would need to know what to look for. So, a group of researchers at the European Space Agency created an experiment called STONE-6. They described their work at the European Planetary Science Congress 2008, held last week in Münster, Germany
Essentially these folks designed an artificial satellite that they mounted on a FOTON M3 capsule launched from Baikonur on September 14th, 2007. It contained two samples of terrestrial sedimentary rock and a control sample of basalt that were fixed to the heat-shield of the return capsule. It re-entered the atmosphere on September 26th after 12 days in orbit. The basalt was lost during re-entry, but interestingly enough, a sample of 3.5-billion-year-old volcanic sand containing carbonaceous microfossils and a 370-million-year-old sample of mudstone from the Orkney Islands each containing chemical biomarkers both survived.
When the scientists examined the surviving samples, they found that a 3.5-billion-year-old sample of sand from Pilbara in Australia had formed a thick, creamy-colored fusion crust (essentially a crust that melted and then solidified around the rest of the sample). The microfossils inside survived nicely. The sample from the Orkney Islands experienced the same fusion crust creation. The rocks also transported an organism called Chroococcidiopsis. The heat of re-entry killed and carbonized this bacteria. But, there were “fossils” left behind.
So, it would appear that past Martian life forms (if they existed) could hitch a ride on a meteorite and survive the trip, we should be able to find them here on Earth when we search for Martian meteorites. This doesn’t mean they did, so I should stress that NO life has been discovered, yet. The trick now is to look for rocks with Martian-type mineralogy AND which have the creamy-colored fusion crust that indicates their trip through the atmosphere. Examine those for signs of biomarkers that aren’t from Earth, and we’ll likely have a big story about life on Mars.
September 28, 2008 at 9:00 am | Leave a Comment
NASA’s Glory Mission to Carry Names
Okay, how many times have you been sitting there reading stuff on your computer and learned about the opportunity to send your name into orbit on a spacecraft? Well, sure there was one a few months back, and maybe another one a few years ago… but hey, my point is, here’s another chance–and nothing says “coolness to the max” like having your name on a spacecraft, right? Darned right! And, if thousands of us do it, it will be (in the immortal words of Arlo Guthrie) a movement.
The latest satellite-based list of names going into space is on Glory mission, which will be launched to help scientists measure aerosols — airborne particles — in our atmosphere.
Of course, we all know that changes in our climate are taking place. Understanding ALL the aspects of our atmosphere is important. You’ve heard of the greenhouse gases that are affecting our climate, and these are important. But, scientists say that the effects of aerosols could play a role in that change.
Glory will carry two scientific instruments, the Aerosol Polarimetry Sensor, or APS, and the Total Irradiance Monitor, or TIM, and two cameras that will be used to help identify clouds. The APS instrument will be the main player in determining how and why aerosols affect our atmosphere. The TIM instrument will continue 30 years of measuring total solar irradiance, which is the amount of energy radiating from the Sun to Earth. Understanding the sun’s energy is an important key to understanding climate change on Earth.
The Glory mission will launch in June 2009 and you have til November 1 to get your name on the spacecraft. So, surf on over to the Glory poll site and enter your name. In return, you’ll get a nifty downloadable PDF to print out and show your friends. I did, and already, I feel tingly cool all over!!
September 27, 2008 at 8:45 am | Leave a Comment
Using a Radiosonde
When I was a little girl growing up in Boulder, Colorado, I remember one day seeing something floating above our house. As it got closer and closer, I could tell it was a balloon. Then, it floated out of sight. Later that day, my dad went out in the field (we lived on a farm) and found an instrument box attached to a limp balloon. He said it was called a radiosonde.
What a cool word! Radiosonde. It sounded so exotic and “outer spacey” to me. Daddy called around and found it was a weather balloon sent up by scientists at the National Center for Atmospheric Research (which had offices and labs in Boulder).
Radiosondes go up into the atmosphere and take measurements of wind speeds, temperatures, altitudes, humidity, and other characteristics. They also measure the amounts of gases in our atmosphere. These balloons have been major players in atmospheric science since the 1930s.
We got to take the radiosonde back to the scientists, although I don’t remember that event too well. But, to me, that radiosonde was a mysterious and exciting link to the sky and our atmosphere. And, it’s interesting to note that scientists use them every day, around the world, to measure changes in our atmosphere.
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Image of Horsehead Nebula: T.A.Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)
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