04 August 2005

Astronomical Updates



Of course ... just hours after my last astronomy posting, another even more exciting discovery was made. Another transneptunian body has been found, even bigger than Pluto:

Astronomers have found a tenth planet, larger than Pluto and nearly three times farther from the Sun as Pluto is today.

Temporarily designated 2003 UB313, the new planet is the most distant object yet seen in the solar system, 97 times farther from the Sun than the Earth is. It also is the largest body yet found orbiting in the Kuiper belt, the group of icy bodies including Pluto which orbit beyond Neptune.

Like Pluto, 2003 UB313 is covered by methane ice, and at its present distance is chilled to just 30°C above absolute zero...

According to some theories, there may be hundreds of large transneptunian objects out there of significant size. Some theories predict at least one body as big as Mars out there...

Should these be considered "planets"? Of course, "planet" is our term, not nature's. Nature doesn't care what they're called, She just makes 'em. But it is becoming apparent that our ancient nomenclature is, well, ancient, and no longer appropriate given the new discoveries and kinds of discoveries we are making. Like Linnaean nomenclature in biology, the old "planet" terminology will eventually be relegated to layman's usage or restricted pedagogical usage.

Update: Oh, also. Titan is dry. Looks like the hoped-for oceans of hydrocarbons may once have been, but are no more.

The Cassini spacecraft has also observed intriguing liquid-related features. It has detected dark, river-like channels since it neared the moon in 2004. And the Huygens probe, which was dropped down to the moon’s surface, sent back detailed photos of channels near its landing site. But Cassini's visible and infrared cameras have failed to find the reflections expected from surface liquid. These instruments measure wavelengths of light ranging from about 0.25 to 5 microns (or millionths of a metre) long.

Now,astronomers observing 2.1-micron-long infrared light at the Keck Observatory in Hawaii have reported similar findings.


It was wet, it was dry, it was wet, it was dry. Certainly a lot of us humans, looking up from our own largely liquid world, had our imaginations captured by the thought of Titanian oceans, even oily ones. But looks like it may (the jury is of course still out) have been wishful thinking. That's ok though. Reality and truth is better in these cases since it increases our understanding and still leaves room where the imagination can dwell.