Cool Science: Part One

Saturn’s Rings Have Own Atmosphere which came as a surprise to me – but I’m not an astronomer or astrophysicist or anything. Apparently, due to some interesting properties concerning the way water (i.e. H20) behaves in the region of Saturn an atmosphere is generated:

Water molecules are first driven off the ring particles by solar ultraviolet light. They are then split into hydrogen and atomic oxygen, by photodissocation. The hydrogen gas is lost to space, the atomic oxygen and any remaining water are frozen back into the ring material due to the low temperatures, and this leaves behind a concentration of oxygen molecules on the ring surfaces and, maybe through ion-neutral chemistry, molecular oxygen is formed, but this is not yet well understood.


Earth’s Early Atmosphere and the Search for Life on other Planets

Model Gives Clearer Idea Of How Oxygen Came To Dominate Earth’s Atmosphere

Researchers interested in how earth’s atmosphere came to be dominated by oxygen have come up with an interesting model to explain why there was a lag between the origin of photosynthesis and the domination of earth’s atmosphere by oxygen.

There were several processes at work. First, gasses emitted from volcanoes combined with the oxygen and acted as an oxygen sink. Second, oxidation of iron from space bombardment acted as a second sink. Researcers found that varying the estimates of iron content in the earth’s crust could change the time frame by up to a billion years in one direction or the other.

Here is how it works:

Earth’s oxygen supply originated with cyanobacteria, tiny water-dwelling organisms that survive by photosynthesis. In that process, the bacteria convert carbon dioxide and water into organic carbon and free oxygen. But Claire noted that on the early Earth, free oxygen would quickly combine with an abundant element, hydrogen or carbon for instance, to form other compounds, and so free oxygen did not build up in the atmosphere very readily. Methane, a combination of carbon and hydrogen, became a dominant atmospheric gas.

With a sun much fainter and cooler than today, methane buildup warmed the planet to the point that life could survive. But methane was so abundant that it filled the upper reaches of the atmosphere, where such compounds are very rare today. There, ultraviolet exposure caused the methane to decompose and its freed hydrogen escaped into space, Claire said.

The loss of hydrogen atoms to space allowed increasingly greater amounts of free oxygen to oxidize the crust. Over time, that slowly diminished the amount of hydrogen released from the crust by the combination of pressure and temperature that formed the rocks in the crust.

“About 2.4 billion years ago, the long-term geologic sources of oxygen outweighed the sinks in a somewhat permanent fashion,” Claire said. “Escaping to space is the only permanent escape that we envision for the hydrogen, and that drove the planet to a higher oxygen level.”

The most intersting part of the article is the last sentence:

“There is interest in this work not just to know how an oxygen atmosphere came about on Earth but to look for oxygen signatures for other Earth-like planets,” Claire said.

Note that the one thing missing in this search for life on other planets is Intelligent Design

Organic Molecules in the Early Universe

Nasa’s infrared telescope (the Spitzer Telescope) has found traces of organic molocules that are believed to be about 10 billion years old:

Using Spitzer, scientists have detected organic molecules in galaxies when our universe was one-fourth of its current age of about 14 billion years. These large molecules, known as polycyclic aromatic hydrocarbons, are comprised of carbon and hydrogen. The molecules are considered to be among the building blocks of life.

These complex molecules are very common on Earth. They form any time carbon-based materials are not burned completely. They can be found in sooty exhaust from cars and airplanes, and in charcoal broiled hamburgers and burnt toast.

The molecules, pervasive in galaxies like our own Milky Way, play a significant role in star and planet formation. Spitzer is the first telescope to see these molecules so far back in time.

The interesting part about this, to me, is that these molecules play a role in star and planet formation. Not being an astronomer I can only wonder at how many other organic molecules play a role in these processes.

You can also go here for more info.

Is There Life on Titan

Titan, one of Saturn’s moons, is the only satellite with a major atmosphere. It is composed largely of nitrogen, argon and methane with traces of hydrogen. Additionally, traces of hydrocarbons (ethane, propane, ethlene, etc) nitrogen compounds (hydrogen cyanide, cyanogen, etc) and carbon monoxide and dioxide have been found.

One of the things Huygens will be doing is testing for signs of life on Titan:

They think the microbes would breathe hydrogen rather than oxygen, and eat organic molecules drifting down from the upper atmosphere. They considered three available substances: acetylene, ethane and more complex organic gunk known as tholins. Ethane and tholins turn out to provide little more than the minimum energy requirements of methanogenic bacteria on Earth. The more tempting high-calorie option is acetylene, yielding six times as much energy per mole as either ethane or tholins.
“The microbes might breathe hydrogen rather than oxygen, and eat molecules drifting down from the upper atmosphere”

McKay and Smith calculate that if methanogens are thriving on Titan, their breathing would deplete hydrogen levels near the surface to one-thousandth that of the rest of the atmosphere. Detecting this difference would be striking evidence for life, because no known non-biological process on Titan could affect hydrogen concentrations as much.

Was the Ordovician Mass Extinction Caused By a Gamma Ray Burst?

From Geotimes:

Given the incidence of gamma-ray bursts in the cosmos, astrophysicists estimate that at least once in the last billion years, a burst has occurred within about 6,500 light years of Earth. Now, astrophysicists at the University of Kansas and NASA Goddard Space Flight Center report that if directed at Earth, such a blast could have prompted the ice age and resulting mass extinction during the late Ordovician, 443 million years ago.

The second largest extinction event in Earth’s history, the Ordovician event killed off 60 percent of all marine invertebrates and is believed to have been caused by the sudden onset of an ice age. However, paleo-climatologists remain uncertain about what triggered the ice age during a warm period with high carbon dioxide levels.

Gamma-ray bursts break down nitrogen, which reacts with oxygen to form nitric oxide and destroys ozone. The reaction also produces nitrogen dioxide, a major component of smog, which again reacts with oxygen to form nitric oxide. This cycle perpetuates ozone destruction and produces more smog, blocking sunlight and triggering an ice age, the researchers say.

The team calculated that a 50 percent decrease in ozone would allow up to three times as much solar ultraviolet B (UVB) radiation to reach the surface. Additionally, Thomas says, “the initial flash would deliver the equivalent of five times the UVB flux of a normal, sunny summer day.”

By extrapolating from data on modern Antarctic phytoplankton exposed to increased UVB by ozone loss over the South Pole, the group concluded that a burst of this size and proximity could likely cause widespread extinctions by affecting the base of the marine food chain.

So, being good scientists, how do we test the idea?

“…searching for evidence of a gamma-ray burst in the geologic record would be quite difficult. Unlike asteroids or supernovae, the bursts are not expected to leave behind any direct evidence. So, if a chemical signature of a cosmic event were to be found at the end of the Ordovician, it would rule out the gamma-ray burst idea — and could point to another cause for the extinction.”

Interesting stuff!

Belated Happy 15th Birthday To The Hubble Telescope

I am so ashamed. Not only did I completely miss Earth Day – but I missed Hubble’s 15th birthday as well. Flog me with a wet noodle!Posted by Hello

Proto-planetary disks in Orion

A Hubble Space Telescope image shows “proplyds,” or protoplanetary disks, in the Orion Nebula.

According to NASA, nebulae, flattened disks of gas and dust, “are the likely birthplaces of new planetary systems. Hubble provided visual proof that pancake-shaped dust disks around young stars are common, suggesting that the building blocks for planet formation are in place.”

Phot and text from National Geographic News

Well, This is Freaking Wonderful

From the New Scientist apparently the network of satellites that monitor environmental health is detiorating badly.

The US network of satellites monitoring the environmental health of the Earth is on the verge of collapse, according to a highly critical report released on Wednesday by the country’s National Research Council.

Six recent NASA Earth-observing missions have been delayed, scaled back or completely cut. Several of the cancelled missions were follow-ups to successful satellite projects.

The US is probably responsible for about half of the Earth-science satellites currently in orbit, says Richard Anthes, president of the University Corporation for Atmospheric Research and co-chair of the committee that produced the report.

Most of the document focuses on research satellites, and Anthes warns that, for example, these map bulges in the Earth that may signal impending volcanic eruptions, track the depleted ozone layer, and analyse changes in soil moisture that may precede a famine. Furthermore, if observational satellites are not replaced weather and hurricane forecasting would suffer.

When current satellites retire, scientists fear there may be a serious data gap. “The planning for new missions should probably have been started five to 10 years ago,” says Anthes. “But the community is now waking up.”

As always, our president is on top of the situation:

President George W Bush’s proposed budget for Fiscal Year 2006 lists Earth studies as one of NASA’s five national objectives. But in that budget, NASA’s Earth science programmes would get $1.37 billion, about 8% less than they received the year before.

Apparently, he’s going to fix the problem by underfunding it – I guess if there is no data all those hard questions about global warming will go away. On the hand, he might be replacing the current program with faith based satellites!

I really don’t get it. One of the main reasons why we enjoy the standard of living that we do is because of the strength of our science and technology and it is vital that we continue to have a strong and vibrant research base. Yet in the last few months we have seen several key areas of research go by the wayside (see here for example). Now I don’t know about y’all but I really don’t want to live in a third world country. Nor do I want my children to live in a third world country. So could we PLEASE go back to doing science. I should also mention Santorum’s attempts to destroy the National Weather Service .

Do you want a seven-day weather forecast for your ZIP code? Or hour-by-hour predictions of the temperature, wind speed, humidity and chance of rain? Or weather data beamed to your cellphone?

That information is available for free from the National Weather Service.

But under a bill pending in the U.S. Senate, it might all disappear.

The bill, introduced last week by Sen. Rick Santorum, R-Pa., would prohibit federal meteorologists from competing with companies such as AccuWeather and The Weather Channel, which offer their own forecasts through paid services and free ad-supported Web sites.
“I believe I’ve paid for that data once. … I don’t want to have to pay for it again,” said Scott Bradner, a technical consultant at Harvard University.

He says that as he reads the bill, a vast amount of federal weather data would be forced offline.

“The National Weather Service Web site would have to go away,” Bradner said. “What would be permitted under this bill is not clear — it doesn’t say. Even including hurricanes.”

And in a bit of hypocrisy:

“It is not an easy prospect for a business to attract advertisers, subscribers or investors when the government is providing similar products and services for free,” Santorum said.

AccuWeather has been an especially vocal critic of the weather service and its parent agency, the National Oceanic and Atmospheric Administration.

The company has accused the federal agencies of withholding data on hurricanes and other hazards, and failing to ensure that employees don’t feed upcoming forecasts to favored investors in farming and energy markets.

Which is ironic considering these comapnies get the dat for their forcasts from the National Weather Service.