Earth and sun and moon

[unixronin]

Closest miss yet:  A 30m asteroid designated 2004FH passed 40,000km (25,000 miles, just beyond geosynchronous orbital distance) from the Earth last night after being discovered only two days earlier by an automated telescope.  This one could easily have ruined a lot of people's days.

Big rocks or not, a new study on insect populations suggests that we may be in the early stages of a sixth mass extinction.  There was already concern about declining bird populations; the new study, covering 40 years of data, seems to indicate we're losing insect species even faster than birds.

Far out:  There are now three schools of thought about the newly-discovered planetoid christened Sedna.  First billed as a tenth planet, other astronomers consider both it and Pluto Kuiper-belt objects; the latest speculation is that it may actually be the first astronomical sighting of a body belonging to the Oort cloud.  Orbital observations suggest that 1700km Sedna, currently three times as far out as Pluto, has a highly elliptical orbit that may take it as long as 10,500 years to complete.

Giveth, and taketh away:  A new hypothesis from Edinburgh suggests that life on Earth could not have arisen if the Earth did not possess both abundant free water and a large moon capabler of raising tides.  If this hypothesis is correct, life in the Universe could be very rare indeed.  (On the other hand, there's the hypothesis -- supported by our ongoing discoveries of extremophile bacteria -- that says given one thousand disparate environments, one of which is theoretically capable of supporting life, life will arise in all of them.)

Big Bang theory:  A new study indicates last November's record-making solar flare was much larger even than originally believed.  The largest previously observed flares were X20 events on 16 August 1989 and 2 April 2001; the 4 November 2003 flare was estimated as an X28 event, but could not be accurately measured because it blinded many observing satellites.  A new study at New Zealand's University of Otago has analyzed the effects of the flare's X-ray flux on the upper atmosphere, and has now reclassified the November 4 flare as an X45 event.  (Fortunately, it wasn't pointed directly at Earth.  Even so, the X-ray flux reaching Earth from the flare was 5,000 times the normal X-ray output of the Sun.)

Reach for the Sky:  Finishing touches are being applied to Taiwan's new 508-meter Taipei 101 Tower, the world's new tallest building since being topped out last July and the first building over a half-kilometer tall.  Its aerodynamic-shelled, double-decked elevators will also be the world's fastest, climbing from ground level to the 101st floor in 39 seconds, and is reportedly contructed to withstand the impact of a fully-loaded Boeing 747 or a Richter 7+ earthquake.

---

[Update: thanks to rbos for catching the 30m/30km typo.]

Comments

[jilara.livejournal.com]

And they're having an argument about whether to "downgrade" Pluto from planet status, due to its resemblence more to Sedna than our official "planets." This one will be with us for a while.
Even more exciting, they seem to have located another couple comets that might become visible to the naked eye. We seem to be in a comet-rich time, right now, rather like the 1830's/40's era. (Some of the same comets?)

[unixronin.livejournal.com]

And they're having an argument about whether to "downgrade" Pluto from planet status

Yeah, I mentioned that.

"How many planets does the solar system have?"
"That's easy - nine! ...No, ten! No, wait, eight! Er...."

I like the practical working definition one astronomer proposed: "Any non-luminous object large enough that its own gravity causes it to assume a spherical shape is a planet."

(Of course, this gives a current working total of at least twelve planets, not counting moons... and there's at least one school of astronomical thought that says the Earth-Moon system should be considered a double planet rather than a planet and a moon.)

[rbos.livejournal.com]

*cough*

30m, not km :)

weeeeee bit o' difference there.

Oops.

[unixronin.livejournal.com]

Bad fingers. No extinction-level event.