Category Archives: Astrophysics

100,000 Stars

100,000 Stars is an online visualization of our solar system’s nearest neighboring stars. It was created by Google’s Data Arts Team (see a write-up of the project here). Although it is perhaps a bit difficult to extract specific useful information from this site, it provides an interesting perspective on our place in the universe, a self-portrait of our galaxy (or at least some subset of it) that could only be possible with a computer visualization.


The Overview Effect

Once a photograph of the Earth, taken from outside, is available… a new idea as powerful as any in history will be let loose.

Starting with this quote from astrophysicist Fred Hoyle, the film OVERVIEW explores the changes in perspective that arrived with manned space flights and accompanying images that showed, for the first time in human history, the tenuous piece of real estate on which we all reside. When viewed from this vantage point, the Earth exists as a complete and unified whole, virtually free of any arbitrary divisions created by humankind. It also appears fragile and alone, something that needs to be fought for, cherished, and protected.

It’s a brilliant and beautiful film. It may be the most wonderful thing I’ve seen so far this year.

The continuing mission of Voyager

One of the most interesting outcomes of the space exploration push in the 60s and 70s was the Voyager program. In August 1977, Voyager 2 was launched on a mission to explore the solar system, followed shortly in September by Voyager 1 (yes, Voyager 2 was launched first, but it travels slower than 1, and has been surpassed). They’ve accomplished a lot, but as Paul Gilster notes at Centauri Dreams, they’re not yet done.

Voyager 1 completed its study of the solar system in 1980 and began its interstellar mission. Voyager 2 achieved this in 1989. At the moment, almost 36 years after their launch, the spacecraft are far out there (but not quite yet out of the solar system, depending on your definition). They’re still sending back scientific information, from such a large distance that it takes light from the Sun over 12 hours to reach them (out to Pluto takes about 5.5 hours). This makes them the farthest man-made objects ever sent out from Earth.

Their scientific missions virtually over, the spacecraft have adopted a new role as artifacts of human civilization, time capsules of everything we were when we launched them. In addition to the craft themselves, which have plenty of meaning (some thoughts on that from Matthew Battle), each of the Voyagers carries on it a Golden Record, a snapshot of our world, a collection of nature images and sounds, snippets of music from a variety of different cultures, greetings in 55 different languages.

planet montage


But space is immense. It will be 40000 years before Voyager 1 comes close to any other planetary system, and even then it will still be 1.6 light years away. There is virtually zero chance that these records will ever reach anything intelligent enough to decode and understand them. In all likelihood they will drift alone through the darkness of interstellar space for far longer than human civilization will be around. So why did we go through the trouble of making them and sending them out? This supposedly futile act has more to do with mankind than with any attempt to contact an extraterrestrial species. In Carl Sagan’s words, 

The spacecraft will be encountered and the record played only if there are advanced space-faring civilizations in interstellar space. But the launching of this bottle into the cosmic ocean says something very hopeful about life on this planet.

Much of the space race had to do with cross-cultural competition, nationalistic displays of military and technological prowess. The Voyager Records are an attempt to acknowledge to ourselves our own impermanence, to rally around the messages of hope and goodwill. Gilster sums it up well,

I think any future archaeologist, human or otherwise, would read into the Voyager spacecraft the desire of a species to transcend itself, hopeful of finding a bridge to other intelligence but pressing on regardless as a way of building meaning into the cosmos.

The Origin of Life

Last night I attended a lecture by the astrophysicist Paul Davies entitled ‘The Origin of Life’. Davies, professor at Arizona State University and chair of the SETI Post-Detection task group (you know someone’s legit if they have an asteroid named after them), discussed the “where, when, and how” of the origin of life on earth, and ways we might begin to answer the question of whether there is life on other planets.

His discussion of the ‘where’ and ‘when’ of life’s origin was pretty vague (a ‘warm pool’ several billion years ago), this shouldn’t be too surprising, since knowledge of that important event is itself pretty vague. His focus was really on the ‘how’, especially in relation to the question: is life special? That is, is it singular event or a cosmic imperative?

An important question that arises in the search for extraterrestial life is: how will we know it when we see it? If a meteorite landing on earth contained traces of life, how would we know? In Davies’ words, “If it looks too much like life we know, we say it’s contaminated. If it doesn’t look enough like life we know, we say it isn’t alive.” He talked a little bit about the role of information theory in determining the rise of complex lifeforms, and how life might better be understood and identified from an information processing point of view, rather than from a chemical one. Life has a way of taking information from its surroundings (environmental conditions, energy sources) and using it to react or produce something. Perhaps we can identify life by looking at these information processing pathways.

Davies’ final remarks were about the search for alternate life on earth. If life is common and will readily occur under the right conditions, then it is likely that it has arisen multiple times here on our own planet. If this is the case, then we should be able to find evidence for organisms (almost certainly microscopic) from an alternate ‘tree of life’ unlike any we’ve seen before (perhaps identified on the basis of amino acid chirality). But we first have to look.