The Universe is 13.73 (±0.12) billion years old.
Seems like if we know so well how old the Universe is, we should probably start celebrating it's birthday, right?
I'm getting increasingly disgusted with the commentary surrounding the new IAU definition of "planet". It's not that I would normally get disgusted... but it must just be a slow news day and everyone seems to have a silly opinion. NPR started off with a statement like "If you have a model of the Solar System, you might want to snap off the ninth planet, Pluto." WTF?!?!
It's not like it's gone. Further, it's still a freakin' planet. It's just a dwarf planet... one of four other dwarf planets. So shut the hell up! Pluto doesn't care. The New Horizons spacecraft doesn't care. Further, no one else would care if there wasn't such a big deal being made about it. Sheesh. (end rant)
We now have 12 planets. Get used to it. 8 are "classical planets" and 4 are "dwarf planets". Expect that last category to get much bigger as time increases.
UPDATE []: Oops. Doug's right. Seems like Resolution 5B that would have added the term "classical" in front of "planet" in the definition didn't pass. A further illustration of how silly this is.
Astronomers have discovered a tenth planet, Lila (see note on name below)... modulo the debate about what is considered a planet; for which I point you to Gibor Basri's great essay: Defining "Planet".
UPDATE [2005-07-30 07:54:47]: This NYT story, "Planet or Not, Pluto Now Has Far-Out Rival", says that the astronomers are informally calling this planet, Xena! (Although Lila is the name they formally submitted to the IAU)
UPDATE [2005-07-31 09:40:31]: The Caltech website has been updated to include a note that the name Lila is not necessarily the name that they submitted to the IAU.
If this "discovery" survives scrutiny, it will be the biggest scientific discovery of all time. Hands down.
Finding the Ultimate Theory of Everything
Could two lookalike galaxies, barely a whisker apart in the night sky, herald a revolution in our understanding of fundamental physics? Some physicists believe that the two galaxies are the same - its image has been split into two, they maintain, by a "cosmic string"; a San Andreas Fault in the very fabric of space and time.
If this interpretation is correct, then CSL-1 - the name of the curious double galaxy - is the first concrete evidence for "superstring theory": the best candidate for a "theory of everything", which attempts to encapsulate all the phenomena of nature in one neat set of equations.
Too cool. We have weather, houston (from "Titan's Streams Like Earth's"):
Many of the same processes that helped shape the Earth are in effect today on Saturn's smoggy moon Titan, a team of international scientists revealed on Friday. [See: "Seeing, touching and smelling the extraordinarily Earth-like world of Titan" and "Islands, rivers and methane springs - latest images of Titan".]
Relying on data gathered directly from the atmosphere and surface of Titan last week by the European Space Agency's Huygens space probe, the scientists said they were able to conclude that a regular pattern of precipitation and erosion is carving out streambeds and leaving behind a layer of "dirt" on the giant moon.
"There is liquid that is flowing on the surface of Titan," said planetary scientist Toby Owen,of the Institute for Astronomy, during an ESA-sponsored press conference. "It's not water -- it's too cold -- but liquid methane. And it flows in the same way it does on Earth."
So, I've been really really disappointed in the NASA/ESA coverage of the descent of the Huygens probe. We got a few badly processed images and very little text or non-imaging data.
This is likely a sciency version of propriety... that is, they don't want you to have a stream of raw data so that they can publish a packed issue of Science or Nature. However, there is no competition with the data (that is, no one else has the same data and is rushing to analyze it). So what gives? Is there no funding for outreach and education? Why is there no Huygens data blog where researchers give you bits of insight into what they're doing to analyze the mounds of data they have?
Well, good thing that the data is, by default public domain. Amateurs have been processing the data, "Enthusiast compositions of the Huygens images", and stitching together the raw images into their own panoramas that are far, far better than anything released by NASA or ESA yet. Check these puppies out:


UPDATE: Mr. Liekens is upset that some people are inline linking to his images so he's begun to move his images around. I'll disable the links to the larger images since they no longer point anywhere.
Link: http://www.esa.int/SPECIALS/Cassini-Huygens/SEMXYGQ3K3E_0.html
ESA has posted a neat timeline of Huygens' descent activity, "Huygens descent timeline" for 14 January. Note that the first event listed corresponds to 1:51 PST (10:51 CET). It will be covered live on NASA TV/Webcast. Note the last entry; we don't expect data to reach Earth until 7:42 PST (16:42 CET).
So the Huygens probe will detach, by firing explosive bolts, from the Cassini Spacecraft today. ("/.: Cassini Robot Lab Successfully Separates") A significant part of my past involved astrophysics, a Master's in such from Berkeley Astronomy and a ton of research involving comparative planetology... most notably, the weather of Saturn's moon Titan.
Here's why Titan is so cool... and why you should pay attention on January 14 when the Huygens probe, released from Cassini today, makes its descent into Titan's atmosphere (Feel free to ask questions in the comments):
Titan is the second-largest moon in our solar system after Ganymede of Jupiter. It has a gigantic atmosphere -- 1.5 times as massive as Earth's! -- and one of only 4 rocky bodies in our solar system with a significant atmosphere (the others are Venus, Earth and Mars). Titan's atmosphere is 90% Nitrogen gas and appears to be very similar to Earth's early atmosphere, with one large difference: instead of a hydrologic cycle with H20 clouds, rain and seas, Titan has methane and ethane clouds, rain and bodies of liquid hydrocarbons (propane, gasoline, acetylene, etc.) on its surface. My undergraduate adviser, Caitlin Griffith, was the leading theorist and observer (she's a bit of both) that argued for this methane cycle... we found evidence of clouds -- see our old Science paper ("Detection of Daily Clouds on Titan" (PDF)) -- and this small amount of cloud coverage has been confirmed by Cassini (see, "Probe sees Titan's Methane Clouds").
So, what's the most intriguing question we still have about Titan? Modulo the recent surface observations, which are weird, I would say it is: What has been able to replenish such a massive atmosphere over time, as in equilibrium it should float off into space because Titan is too small to have enough gravity to hold onto it?
Link: http://www.nasa.gov/multimedia/imagegallery/image_feature_216.html

Wheel tracks left by NASA's Mars Exploration Rover Spirit, and even the rover itself, are visible in this partial image from the Mars Orbiter Camera on NASA's Mars Global Surveyor orbiter
Link: http://sciencenow.sciencemag.org/cgi/content/full/2004/825/1?etoc
(You or your institution will have to have a subscription to Science to click through the link above.)
When it comes to extrasolar planets, smaller is better--at least for astronomers, who long to find worlds like Earth. A European team now has taken a step toward that goal by spotting the smallest planet yet found circling an ordinary star. The planet weighs in at 14 times Earth's mass, and although the astronomers have no direct evidence of the planet's composition, it may be the first known alien world made mainly of rock, rather than gas, in a planetary system like our sun's.
[...]
The planet races around µ Arae at less than 1/10th of the distance between Earth and the sun. According to models of planetary formation, an object of that size is too small to have coalesced farther out as a gas giant and then migrated toward the star. Rather, Santos says, it probably formed near its present orbit by accumulating a hot core of rock and a relatively small gaseous atmosphere.
Because the planet does not cross directly in front of its star, the team cannot confirm its inferences by measuring the planet's radius, says planetary theorist Alan Boss of the Carnegie Institution of Washington in Washington, D.C. Still, Boss finds the logic convincing: "They seem to have found what I would call the top end of the range of terrestrial-type planets. This is a very encouraging sign that we will find a lot of lower-mass rocky planets in the next 10 years or so."
This is wicked. We'll find many more like this in the coming decade (by 2010). I expect the announcement of an Earth-sized planet areound a Sun-like star to be within the year (end of 2004). I also expect the same but in an Earth-like orbit will be found within three years (September of 2007).