For the past several days headlines all over the web have read “US to shoot down satellite.”

Ok, first off, that satellite is on its way down no matter what. That would be the problem. It doesn’t actually need shot “down.”

Second, after it gets nailed by whatever our government and military, in their wisdom, decide to fire at it, the satellite is going to hopefully smash apart into a bazillion little pieces, and some of those pieces will end up going up, while others stay in orbit, so in reality we are shooting the satellite in all directions.

An accurate, and still fantastic, headline should read, “US plans to blast satellite into little bits” or “US plans to blast satellite apart.”

The only reason this is happening is to guarantee that the satellite is in tiny enough pieces as it comes through the atmosphere that nothing makes it through intact. This is a dangerous thing to do because bad aim could knock it in unpredictable ways that lead to much badness (for instance, a glancing blow with failure to detonate could set the thing spinning and put it on a new orbital path that hits Earth sooner). Alternatively, we could blast it into a bunch of tiny pieces and a few big ones that wreck havoc either on Earth or in space. It’s not like Earth’s orbit really needs more space junk, but… More space junk is better than toxic chemicals killing a bunch of people on Earth. This is probably the best thing to do, and the best thing isn’t always a safe thing.

Bottomline: Weather willing the US will be blasting apart a satellite somewhere over the Pacific nearish Hawaii during the darkest part of the lunar eclipse tonight (so they can better see falling chunks – this has a good scientific reason). We are not shooting it down. It’s already on its way down. They’re just skeet shooting a really large metal pigeon filled with poison.

Want to learn more about the satellite (USA 193, for those wanting to know)? Check out Phil’s Bad Astronomy Blog. He’s got a video that gets into all the details.

Mercury is a sun-baked world, with surface temperatures typically sufficient to cook a turkey and humidity levels that make the sub-Saharan desert look excessively humid. This little world is locked in a strange gravitational dance with the Sun, which causes it to rotate on its axis only 1.5 times during its brief 88 Earth-day year. This means 1 day on Mercury stretches across 58.7 Earth days. During its languid rotation, it very precisely keeps its poles pointed straight up and down – there is none of the tilt that on Earth provides us out seasons. This means that its poles never face the Sun and within the depths of it’s polar craters there are places that only know darkness. In those shadows, Mercury actually has ice. But… Where the Sun hits their is nothing but baked metallic dirt.

Its small orbit keeps Mercury always within 28 degrees of the Sun. In a perfect world, Telescopes never get within 30 degrees of the Sun and objects are measured when they are within 45 degrees of straight overhead. Mercury forces us to either observe it during the day when it is high in the sky (which can be done, but gets the telescope hot and makes it useless to night time observers), or in twilight when it stands out against the coming darkness but twinkles violently in the atmosphere. From Earth, it is impossible to take detailed images of this little world. It just doesn’t know how to line up for a picture in a proper location. So… we send out probes, and maybe in January we’ll finally at least know what all the sides of Mercury look like. Today, all we have is a crescent image from Mariner 10.

Venus too, is over heated, but while the Sun definitely provides the energy to necessary to keep the planetary inferno roaring, it is actually Venus’ atmosphere that is too blame. Composed primarily of carbon dioxide, sulfur dioxide, sulfuric acid, and other green house gases, the planet’s clouds prevent Venus from cooling to temperatures that allow liquid water to collect. Average surface temperatures are over 450C (a temperature my sad old stove can’t achieve). Exactly what caused this world to self-destruct is a hard to understand.

It is thought this world may once have had water oceans not too different from our own, but when they evaporated for reasons that are being argued, a run away green house effect began. It is possible that Venus had life that was destroyed (I’m talking about microbes or bacteria). It is possible that we could trigger on our planet the same catastrophic green house effect. Once out oceans start to noticeably evaporate, really, we’re dead. (And like with Venus, the heat, storms, and potential acid will eradicate any possible surface signs that life one existed).

Part of me has always felt that understanding Venus is one of the most important things we could do. People often talk about terraforming Mars, but Mars is a little world with out enough gravity to hold on to any atmosphere we manage to put there. Venus is a little bigger than the Earth, and clearly likes to be cloudy. If we could somehow figure out how to end its greenhouse effect, we could learn how to save our planet, and we could have a neat, acid etched planet to explore. Admittedly, the Sun is just waiting to irradiate both the worlds in a few tens of millions of years, and at that point Mars is really the better world to hide on, but… that’s tens of millions of years away.

So, (I’m not saying this is a good idea, I’m just saying it’s an idea), I vote for thinking about figuring out how to end Venus’ green house effect. If we can stop green house gases there, we can stop them anywhere. Go Venus Express, go.

For some strange reason, the ideas of moving life around the solar system on rocks / comets / other random objects and alien life have been coming up a lot with me this week. First blogged on the probabilities of finding radio signals from aliens (hat tip to Fraser on that one), then Fraser and I talked with Swoopy about the new National Research Academies Report on things we need to think about in trying to find life on off of this world. And now… The Universe is jumping in and bringing up alien life as well.

And when talking about alien life in the solar system, I always thing about panspermia.

One theory off life states that life didn’t originate on Earth but was rather carried here from another world. Research done by J. Melosh (and talked about in Life as We Do Not Know It), shows that at most maybe 1 or 2 rocks could have made it out of our solar system in the past 4.6 billion years or so. So… assuming that other solar systems are equally likely to fling rocks around the galaxy, it is close to impossible that another solar system managed to fling a rock filled with life out such that it arrived here and landed on Earth at just the moment the Earth started to be able to support life. This basically throws the idea of galactic panspermia originating life on Earth out the window in my (admittedly non-expert in this area) mind. What isn’t eliminated is the possibility of life originating at some other place in our solar system.

Early in the Solar System’s life, toward the end of its first billion years and beginning of its second billion years, there was a period of heavy bombardment when vast numbers – tens of thousands – of asteroids capable of creating craters and carnage hit the Earth. These rocks from space not only donated their mass to planets like Earth and Mars, but in some cases they hit planets with so much energy that they caused pieces of the planet’s to fly into space. During this period, the exchange of bacteria and microbes would have been possible between worlds.

Evidence of former oceans on Mars (in the form of hematite and subsurface ices) and its greater and safer distance from the Sun, may have made it a safer initial place for life to evolve. It’s distance kept it a little cooler when the Sun was younger and hotter, and the distance would have also helped life cope with the young Sun’s extremely powerful coronal mass ejections.

I’m not convinced this is the way things happened. I personally fall into the “Deep sea trenches look like a nice place to start life” camp, but as a scientist I have to admit that I don’t have enough information to say life originating on Mars is a scientifically invalid idea. Its quite possible that panspermia worked and life was actually carried from there to here, as life flew through the air (and the vacuum of space).

One of the things it particularly emphasized (that I don’t think is generally talked about enough) is the importance of a magnetic field in maintaining a planetary atmosphere.

The Earth, which still has its atmosphere, is significantly larger than Mars, and we are still cooling off as a planet. Once upon a time, our world was so hot that volcanoes were going off all around the globe, and the material they threw into the atmosphere settled into a noticeable layer of soot. Today, our world is a bit calmer, a bit cooler, and a bit less messy. Given enough time, volcanism may die out altogether as our planet cools and its liquid iron core solidifies. When that happens, our planet’s magnetic field will also die down and the magnetosphere will disappear.

To get a picture of what this means, we need only look one world out. Mars already cooled off and lost its magnetic field. Here on Earth, when the solar wind hits our magnetosphere or when a coronal mass ejection blasts our way, nothing too exciting generally happens. There will be pretty aurorae, and sometimes the ionosphere will bloat in size and a few satellites or a part of the power grid will get knocked out. While bad, these things inconvenience civilization more than they effect the ability of life to live on. On Mars, the solar wind and CMEs just blast Mars’ atmosphere away. This means Mars is losing its atmosphere for multiple reasons: it gravitationally can’t hold on to warm, fast moving gas particles, and the Sun is blasting away gas particles that aren’t moving fast enough to escape on their own.

There is an excellent book on terraforming and settling the Red Planet called Red Mars by Kim Stanley Robinson. It talks about how it is possible to slowly add oxygen to Mars over generations by introducing specially selected and sometimes engineered plants. Unfortunately, without being able to put back the planet’s magnetosphere, the Red Planet’s surface will always suffer from high radiation levels and will remain dangerous for DNA-based many celled organisms.

Let’s hope the Earth takes its own sweet time cooling off.

One final word on “The Universe: The Red Planet”: I have to say this second episode was much better than the first episode in terms of pacing and use of graphics. It was an amazing example of what a good production team can do with access to NASA multimedia and some really good talking heads. There was one humorous moment when they had some rather confusing verb tenses for the planned 2007 summer launch of Phoenix. It was clear they planned to air the episode after the summer and after the launch. Oh well – these are the risks of trying to write on the cutting edge. Still, it was good, and I recommend giving it a watch. Click here or check your local listings to find out when it is airing on The History Channel in your time zone.

Right now there is a box of boxes on my back stoop that is human-sized in volume, and almost human massed (see picture: note single serving Silk yogurt for scale). It is the result of shopping online where the selection is higher, the prices are often lower, and sometimes there is free delivery. Amazon, Drs. Foster and Smith, and eBay are all to blame. As much as I hate the mega-malls, the strip malls, and, well, even the local mall, I have to wonder if their isn’t a more eco-friendly way to purchase the things that can’t be acquired on a walk through the mom and pop stores of main street?

Paper is not an inherently bad product. In fact, the fast growing trees that are used to make domestically grown papers are good for the environment. Given the choice of paper or plastic, paper may be the more sound option – If the paper bag blows away and get wet, it turns to mush. That plastic bag is just going to blow free, waiting to get stuck in a tree, wrap itself around an animal, get chocked on by an animal, or otherwise do something bad. Similarly, cardboard boxes are something I can bury in my garden under a layer of bark mulch and know that (assuming I remove all the tape and staples) they will decay to worm food after one weed blocking season. The plastic just keeps blocking the weeds on and on and on.

The real problem with our catalogue ordering, Amazon clicking, box filled society is that we are consuming far more resources than are necessary. There have been days when the UPS dud has come to our house twice and the DHL and FedEx guys have each taken their turns as well. That’s a lot of gas, a lot of plastic filling materials, and a lot of cardboard all used to bring use a few objects that would all have fit in one backpack. Particularly troubling is the addiction to 2-day air mail that comes with our Amazon Prime membership. Every planeload of wares is a major insult to the environment – but our household desire for instant gratification keeps those planes flying.

Environmentally responsible shopping requires one to buy locally grown and manufactured goods that preferably come from environmentally responsible companies. Like the Tuscans, we should learn to eat what is in season, and savor the favorite foods of the current crop rather than demanding out-of-season apples in May. Unfortunately, our centralized economy has largely adapted to our generic unchanging needs, so soybeans for cows come from where I live, and soybeans for people come from Wisconsin, while non-soy food comes from somewhere else. Instead of growing everything everywhere, we grow something somewhere and ship it everywhere. This process has its own efficiencies, but it unbalances ecosystems, makes entire crop destruction possible with one foul storm, and keeps lots of long haul shippers employed when their spouces would likely live it if they just did a daily dairy run.

When Wal-Mart and the other big box companies (who require centralized production to get the needed amounts of inventory) put mom and pop stores out of business, they are also ruining the environment by feeding out “Everything now” mentality.

Not that I help the environment when I order my garden plants and compost bin from the web — there are ironies in the environmental movement.

So, having stared at my personal cardboard box pile and contemplated my environmental fingerprint, I’m going to pledge to myself that I will try to spend $1 in a local store with local products for every $1 I spend online, and I’m going to swear off air freight (at least until Harry Potter comes out…).

One small step at a time, maybe we can all reduce our environmental finger print or at least the amount of mass that goes through the mail.