First exoplanet within the habitable zone (and also earth-like density)

I'm going to quote the press release below, but first let me say that this is awesome.  Now, we've got absolutely no evidence for anything living there yet, but, what we do have is:

•  A rocky planet with enough mass to maintain an atmosphere.
• A rocky planet a distance from its sun that puts it within the zone where liquid water, solid water, and gaseous water may all exist at the same time.
• A rocky planet with one side tidally locked to its star.

What does this mean?  Well, if the planet has enough mass to maintain an atmosphere, the only reason it WOULDN'T maintain an atmosphere is if its star stripped it away through certain kinds of activity; the star, though, is massive enough that it's not really the type to have many flares, so it's probable that there is an atmosphere on this planet.

The planet is close enough to the star that its year is only 37 earth-days long.  That's closer than Mercury to our sun.  However, our sun is not a red dwarf like Gliese 581.  This means that Gliese 581's luminosity is much lower than our sun's--a planet would need to be a lot closer to the star to be in its habitable zone.  It also means that---I'm being sci-fi here---if life has evolved on this planet, and life also evolved complex organs, including eyes, the beings there would see at a different wavelength from us.  Neat!

Additionally, due to the tidal-locking (very similar to how we only ever see one face of the moon), 1/2 of the body would be always in shadow (cold) and 1/2 of the body would always be in light (warm/hot).  This means that there would be a narrow strip along what's called the terminator (although it doesn't exactly apply when a body has an atmosphere)--the boundary between night and day--that would be the ideal habitat for any creatures living on this planet.  There have been some interesting short short stories about such places, though I can't remember their names or their authors, so you'd have to go look for them yourself.

Anyway, it's pretty cool that we're now able to find planets that are only 3-4 times as massive as our home...  Soon, we should be able to say what kind of atmosphere these planets have, and then we should be able to argue whether or not they have any kind of life on them...

http://www.nasa.gov/home/hqnews/2010/sep/HQ_10-237_Exoplanet_Findings.html

NASA and NSF-Funded Research Finds First Potentially Habitable Exoplanet

 

 

WASHINGTON -- A team of planet hunters from the University of California (UC) Santa Cruz, and the Carnegie Institution of Washington has announced the discovery of a planet with three times the mass of Earth orbiting a nearby star at a distance that places it squarely in the middle of the star's "habitable zone." 

This discovery was the result of more than a decade of observations using the W. M. Keck Observatory in Hawaii, one of the world's largest optical telescopes. The research, sponsored by NASA and the National Science Foundation, placed the planet in an area where liquid water could exist on the planet's surface. If confirmed, this would be the most Earth-like exoplanet yet discovered and the first strong case for a potentially habitable one. 

To astronomers, a "potentially habitable" planet is one that could sustain life, not necessarily one where humans would thrive. Habitability depends on many factors, but having liquid water and an atmosphere are among the most important. 

The new findings are based on 11 years of observations of the nearby red dwarf star Gliese 581using the HIRES spectrometer on the Keck I Telescope. The spectrometer allows precise measurements of a star's radial velocity (its motion along the line of sight from Earth), which can reveal the presence of planets. The gravitational tug of an orbiting planet causes periodic changes in the radial velocity of the host star. Multiple planets induce complex wobbles in the star's motion, and astronomers use sophisticated analyses to detect planets and determine their orbits and masses. 

"Keck's long-term observations of the wobble of nearby stars enabled the detection of this multi-planetary system," said Mario R. Perez, Keck program scientist at NASA Headquarters in Washington. "Keck is once again proving itself an amazing tool for scientific research." 
Steven Vogt, professor of astronomy and astrophysics at UC Santa Cruz, and Paul Butler of the Carnegie Institution lead the Lick-Carnegie Exoplanet Survey. The team's new findings are reported in a paper published in the Astrophysical Journal and posted online at: 

http://arxiv.org

"Our findings offer a very compelling case for a potentially habitable planet," said Vogt. "The fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common." 

The paper reports the discovery of two new planets around Gliese 581. This brings the total number of known planets around this star to six, the most yet discovered in a planetary system outside of our own. Like our solar system, the planets around Gliese 581 have nearly-circular orbits. 

The new planet designated Gliese 581g has a mass three to four times that of Earth and orbits its star in just under 37 days. Its mass indicates that it is probably a rocky planet with a definite surface and enough gravity to hold on to an atmosphere. 
Gliese 581, located 20 light years away from Earth in the constellation Libra, has two previously detected planets that lie at the edges of the habitable zone, one on the hot side (planet c) and one on the cold side (planet d). While some astronomers still think planet d may be habitable if it has a thick atmosphere with a strong greenhouse effect to warm it up, others are skeptical. The newly-discovered planet g, however, lies right in the middle of the habitable zone. 

The planet is tidally locked to the star, meaning that one side is always facing the star and basking in perpetual daylight, while the side facing away from the star is in perpetual darkness. One effect of this is to stabilize the planet's surface climates, according to Vogt. The most habitable zone on the planet's surface would be the line between shadow and light (known as the "terminator"). 

We Are all Going to Die of Heart Failure Because we Sit at Desks for Eight Hours a Day!!!! Wait, Whatever Happened to Fact Checking?

A friend of mine shared this link via Google Reader. This is Kottke's reading of the New York Time's complete bungling of a medical report published in Medicine & Science in Sports & Exercise. This bungling is so bad that I'm inspired to rant (okay, just about anything inspires me to rant, but this seemed an appropriate forum for this rant).

Kottke read the NYTimes article and didn't actually follow through to read, in any more detail, the actual report.  They're at fault for just blindly reading something from NYTimes without checking it out.  They're at fault for then publishing what they read as fact, and for quoting an "authority" without making sure what they read was from the original source.

NYTimes is just plain wrong.  They apparently couldn't read to the end of the abstract before running off to be the ones with the scoop.  From their article, one would have to assume that those of us with desk jobs are doomed to die from Cardiovascular disease (CVD), no matter how much we exercise at other times.

I don't have access to the full article, unless I want to pay some ridiculous fee.  However, the abstract is freely available here.  The results and conclusions sections of the abstract are reproduced below, with my emphasis added.  Since I don't actually do any physical activities other than type, I'm pretty much doomed, but those of you who exercise for health reasons, don't stop just because some dumb reporter can't read to the end of a page.

Results: Three hundred and seventy-seven CVD deaths occurred during 21 yr of follow-up. After age adjustment, time riding in a car and combined time spent in these two sedentary behaviors were positively (P_trend < 0.001) associated with CVD death. Men who reported >10 h·wk⁻¹ riding in a car or >23 h·wk⁻¹ of combined sedentary behavior had 82% and 64% greater risk of dying from CVD than those who reported >4 or >11 h·wk⁻¹, respectively. The pattern of the association did not materially change after multivariate adjustment. Regardless of the amount of sedentary activity reported by these men, being older, having normal weight, being normotensive, and being physically active were associated with a reduced risk of CVD death.

Conclusion: In men, riding in a car and combined time spent in these two sedentary behaviors were significant CVD mortality predictors. In addition, high levels of physical activity were related to notably lower rates of CVD death even in the presence of high levels of sedentary behavior. Health promotion efforts targeting physically inactive men should emphasize both reducing sedentary activity and increasing regular physical activity for optimal cardiovascular health.

Extraterrestrial life? Not Based on Water?

Ars Technica, a geek news site has an article pulling a sentence out of an abstract about the chemistry on Saturn's moon Titan.  They latch onto the idea that certain chemical processes producing some weird abundances in Titan's atmosphere could be caused by a methanogenic life form.  Methanogenic here means based on methane as the solvent rather than water as the solvent.  This idea has been around for a while, and is perfectly reasonable.

Of course, the peculiar abundances could be caused by some simple chemistry and most of the scientific article discusses that simple chemistry, but why would a geek news site that thrives on far-out ideas write an entire article discussing the possibility of simple chemistry when it can talk about our new overlords from Titan?

Regardless, it's still interesting.  And I'm still wishing I was asleep instead of blogging at 7:32 Eastern Daylight Time (4:32 My Body's Standard Time), but I've got to get going to crush more young researcher's dreams of pauperdom and drive them into industry where money is easier to come by.

What's the Big Deal About Toyota's Cars?

I need someone to explain this to me:  There have been something like a few thousand reports of sudden unintended acceleration on all of the ~30 million Toyota vehicles sold since 1999.  That's something like 0.00667%.  Let's be generous and say there are 10x as many problems as reported.  That's still 0.06667%.  That is, there are about 70 incidents for 100,000 vehicles, with a much lower rate of injury and even lower rate of death.

Why are we wasting our time on this but not bothering to deal with real problems?  What are we doing to fix human-induced climate change?  What are we doing to fix problems with access to clean water?  What are we doing to fix the 40,000 gun-related murders in the US every year?  What are we doing to deliver better, cheaper health care to our citizens?  What are we doing about Darfur?  What are we doing about the five million people injured or killed due to alcohol-related vehicular accidents?

In short, why is everyone freaking out about such an irrelevant "problem" when there are real problems to deal with?

I'm Sorry, Son.

The Copenhagen Accord is an unmitigated disaster. Sure, it looks reasonable, the two largest polluters have agreed to take a look at their emissions and possibly decide on a target sometime in the future.

As I've said before, the international community has just a few years to agree to, engineer, and implement a full solution. We're expected, on our current course, to hit 650 ppmv CO2 by 2100. That's without all possible feedbacks included, such as methane release from the ocean bottom, or sudden and complete melting of the permafrost.

If we can't even agree to our limits until 2020, there is no possibility of reducing them enough to avoid 2 or 3 degrees C warming. I've hinted at problems associated with various warming scenarios before, but here are a few that we are going to see. Not "might" see, but going to see because of the failures of vision at the Copenhagen summit.

This is what's going to happen as we hit 2 degrees C warming, which was avoidable ten years ago, mostly avoidable five years ago, and is completely unavoidable now:

• Dramatic changes to weather patterns worldwide
• Elimination of fresh water for 1/3 of world's land surface
• Permanent drought in US southwest, Australia, and Africa
• Much of inner Australia will burn
  
• Aquifer levels under the US Great Plains, Saudi Arabia, and Northern China are falling fast, without replenishment.
• Rise of sea levels by at least 1.2 meters (2.75 billion people affected)
• Food & water shortages will cause unstable States to fail:
• African states, Pakistan*, North Korea*, Somalia, Iraq,
• India*, China*, Afghanistan, Israel* Sudan, Lebanon*, ...
• 1 degree of warming: wheat, corn, rice yields drop 10%.
• Global food reserve was at less than 62 days and declining in 2008.
  
• Disease epidemics will become worse and last longer
• Over-Consumption is worse than high population.

Those states with a "*" after them are declared or undeclared nuclear states. We need to plan on Pakistan and North Korea failing or worse within the next 50 years. India's inability to provide clean water to its 1.1 billion people is going to make it unstable in the next few decades as well. China may be able to weather most of the problems, but its lack of clean water is going to be a huge problem to its 1.3 billion people. In 1997, Israel was withdrawing 287 cubic meters of water per capita. It's available resources were only 265 cubic meters per capita. The extra 8.3% came from other countries.


At 3 or more degrees C warming, we will see the following (in fact, some of this is happening already--we don't fully understand all of the feedback mechanisms):

• At or above 2 degrees of warming, positive feedback systems become active.
• Permafrost will begin to melt more quickly, releasing CO2.
• Methane will be released from the seafloor bottoms, adding more GHG to atmosphere.
  
• Composting rate of organic matter increases, CO2 release.
• Amazon forest, grasslands die & burn, releasing CO2.
• Plants begin to release CO2 instead of absorbing it.
• At 3 degrees warming, run-away permafrost melting will begin, releasing more and more CO2.
• 3-4 degrees warming is avoidable if we cut emissions by 80% by 2020.
  
• At 6 degrees warming, hydrogen sulfide gas makes up a large part of the atmosphere.
• We will hit 5-7 degrees of warming by 2100 at current emission growth rate of CO2.

Since the Copenhagen Accord doesn't commit anyone to cutting emissions 80% by 2020, but instead commits nations to talking some more, we have guaranteed 3-4 degrees warming, and that means that feedbacks will almost guarantee 5-7 degrees of warming by 2100. With the last, best hope having faded, we need to start talking about large-scale adaptation in addition to mitigation. See the blue arrow in the graphic below? That assumes that next year we'll start cutting emissions, not just talking about it, but actually cutting. So, we're looking at the orange or, more likely, the red arrows.






So, let me just say, son, that while we love you, we didn't think your future is important enough to protect by sacrificing any of our own comfort. Sorry. We hope that some of you will forgive us, but understand if that's difficult to do. Also, those morons who thought it would be a good idea to dump billions of tons of chalk into the oceans in 2025? We didn't do anything to stop them because, well, we just couldn't be bothered.

[edit]
See this video of a talk at AGU last week.
http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml#

Population Control a Solution to Human-Induced Global Climate Change?

No.

I've seen more than a few suggestions that population is the problem to global warming/global climate change and therefore The Solution is population control.

There are three, surprisingly unrelated issues in the above statement.

First, the world is probably overpopulated. There are all kinds of discussions of the carrying (PDF) capacity (PDF) of the Earth. Most conclude that we've met that carrying capacity and that we're living on borrowed time. How much time is, of course, not clear.

As some examples of the idea that we've reached the limit of our ecosystem's carrying capacity:

In 1999, it was estimated that the world had about 116 days of food reserves stored. That is, if all food production stopped, we'd have about 116 days of food available to feed everyone in the world. As of 2006, those reserves had shrunk to 56 days.

Many people (PDF) agree (PDF) that we've reached the peak of oil production and that oil and its derivatives will become more and more difficult to acquire. That matters because all kinds of quality of life issues are directly related to availability of (cheap, easy) energy supplies. That is, we can extend the carrying capacity of an ecosystem by introducing external energy sources.

Human-induced global climate change is due, basically to resource utilization. There are too many of us and we're consuming too much energy making too much stuff.

From those three examples, I'm going to move on with the assumption that everyone agrees that we've reached (some kind of) carrying capacity of our ecosystem. That is, the earth is overpopulated by humans.

Can we solve that last example by limiting births? First, we have to understand the problem. I've posted several times about the problem of human-induced climate change. The biggest problem with our releasing of CO2 into the atmosphere is that there is a lot of inertia in the atmosphere. We're at 385.99 parts per million by volume CO2 (ppmv) in the atmosphere. During the Cretaceous, the atmosphere was at 340 ppmv but was 5 degrees C warmer (on average). Why aren't we this warm yet? Because it takes time for the atmosphere to respond. We may not get that warm this time, but even if we cut all CO2 emissions to 0, we'd still warm at least 1 to 2 degrees C over the next few centuries.

That's where the problem comes in. The scientific publications and the press are talking about 2050 (or something similar) as a target date for limiting CO2 concentrations, but we're already above the concentrations that will push us to 2 or more degrees C of warming and all of the associated problems. Those problems will not be slight, nor will they be easy to adapt to, but they will not be completely catastrophic for the entire human race. Some people in some places will suffer a lot more than others.

Now, with that in mind, let's go back to the idea of population control. We're expected to hit seven billion people within the next decade. For this little thought experiment, let's go with something simple and say we have no (0) births for 10 years. That is, we leave the world population at 6,790,062,216 (July 2009 est.) for the next 10 years. Our emissions of CO2 are growing at a rate of about 2-3% per year. Assuming all of that is due to population increases (which it isn't) and we would stop increasing our CO2 emissions (but not stop emitting), we'd still be emitting about 1.8 ppmv per year. So, we'd still be increasing our CO2 emissions over the 10 years of no population additions (and some population decreases, which I'm ignoring for the moment). So, we wouldn't stay at 385.99 ppmv over the decade of no births. We'd still be increasing, and we'd still be causing irrecoverable harm.

I ignored deaths in the above estimates. Let me correct that here. Let's assume, for a second, that the 1.8 ppmv of CO2 emissions per year is evenly distributed to all humans (it's not--more in a bit). Let's also assume the CIA estimate for death rate (8.2 per 1,000 people) is an accurate average. First, there is an average of 56 million deaths per year (assuming no increase) for the decade of no births. That's a decrease in the world population of 560 million people. Out of 6790 million people. We'd be down to 6230 million people (6.23 billion). Let's now go back to emissions. 1.8 ppmv per year for all 6790 million people is about 2.7 x 10^-4 ppmv per person per year. If we had "only" 6230 million people at the end of the decade, we'd be down to 1.65 ppmv per year. Or a rather slight decrease in emissions by the end of the decade of no births. We'd still be emitting too much, and it would be too late to do anything about it!

There's a huge problem with all of the above: Emissions are not equally divided. In fact, the five largest energy users (68%) account for only 36% of the world's population. That means that controlling population will only have an effect on emissions after many generations, by which time it would be way too late.

We need to control emissions, not population. At some point we'll have to deal with population, but it's NOT the solution to human-induced global climate change. It's not even A solution. It's a solution to exceeding carrying capacity, but it would be too little, too late to affect climate change... Unless people are advocating the removal of the 36% who pollute the most, which I'm sure is not the case since most of the people advocating population control are a part of that 36%. Even if we killed off "the other" 64% of the population as a "solution" we'd only buy ourselves a few decades at our current consumption.

An Earth-Like Exoplanet With a Very Alien Atmosphere

Some time ago, I missed posting about the discovery of a (large) Earth-like planet discovery. COROT-7b was discovered earlier this year. It's about 1.7 times the diameter of Earth, and has about the same density. That is, it's made of rock. Most exoplanets we've seen are made of gas, so this was a cool discovery. I dropped the ball on posting about it. I apologize.

Now, however, some people whose modeling (PDF) work is exemplary decided to have a little fun with this planet. See, it orbits its star with a year that is about 20 hours long. That's very, very, very close to the star. Mercury's orbital period (its year) is about 88 of our days. The closer you are to the sun, the faster your orbit.

So, this rocky planet is very close to its sun. That means that it is so close that its daytime temperatures reach 1800 to 2600 Kelvins (there is no "degrees kelvin", it's just Kelvins). That's hot enough to vaporize rock. Therefore, rock will likely be vaporized from the surface of this planet.

Now, whether this planet has a day-night cycle or is tidally locked so one face always sees the sun is unclear. And not particularly relevant to this discussion. See, if the planet has a diurnal cycle, then the nighttime comes for the area that had rock vaporized. If it doesn't, then the hot atmosphere moves to the cold side due to density (and other) differences. Either way, this hot atmosphere of minerals will condense out as it moves to the cold side of the planet. That is, you would see molten rock falling from the sky. Then (possibly very short-lived) rivers of molten rock flowing on the surface. In some instances, you might even get pebbles raining out (think hail) if the winds are strong enough and the temperatures low enough.

Not only that, but because of the atmospheric temperature differences, you'd have different layers of mineral vapors at different heights. Quite a view, I would imagine.