Sky & Telescope's News Bulletin - Apr 9

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* * * SKY & TELESCOPE's WEEKLY NEWS BULLETIN - April 9, 2004 * * *

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Welcome to S&T's Weekly News Bulletin. Images, the full text of stories
abridged here, and other enhancements are available on our Web site,
SkyandTelescope.com, at the URLs provided below. (If the links don't work, just
manually type the URLs into your Web browser.) Clear skies!

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BUILDING PLANETS IN PLASTIC BAGS

Last year astronaut Donald R. Pettit (NASA/Johnson Space Center) was aboard the
International Space Station preparing his weekly Saturday Morning Science
program, in which he performed various experiments highlighting the fun things
one can do in microgravity. Before him were plastic bags containing salt,
sugar, and coffee grounds. The demonstration he had planned that morning was
fairly mundane -- shake the bags and watch what happens. Little did Pettit know
he might be about to solve experimentally one of most perplexing paradoxes
surrounding the formation of planets.

For decades theorists have had trouble growing planets starting from small dust
grains in a protoplanetary gas-and-dust disk. Given a turbulent disk
environment with high winds and high-velocity (100 meters/second) impacts
between objects, small, millimeter-size clumps should have difficulty growing
to centimeter size and larger without breaking back into millimeter fragments.
No one had ever seen it work experimentally.

Pettit proceeded to take the bags of particles and shake them in front of the
camera....

http://SkyandTelescope.com/news/article_1236_1.asp

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HUBBLE SERVICING: ROBOT TO THE RESCUE?

While astronomers and politicians continue to debate NASA's decision to cancel
further shuttle missions to the Hubble Space Telescope, engineers are looking
for other ways to keep the orbiting observatory alive as long as possible.
Already they're changing how they operate the telescope to circumvent or delay
inevitable hardware failures. And they're looking at the possibility of
dispatching an advanced robot to perform some, if not all, of the servicing
tasks that were originally to be carried out by space-walking astronauts....

http://SkyandTelescope.com/news/article_1233_1.asp

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STAR FORMATION PEAKED LATER THAN THOUGHT

We see lots of stars forming in the universe today, but in fact the most
frenzied action has already occurred. Astronomers agree that the star-formation
rate all across the cosmos peaked many billions of years ago. But exactly how
long ago did this milestone occur, and what was the maximum birth rate of stars
compared to today's? Determining this rate is critical to understanding how the
universe evolved and took on its present-day character.

A new study by Alan Heavens (University of Edinburgh, Scotland) and three
colleagues finds that starbirth peaked about 5 billion years ago, when gas
clouds were churning out stars at a clip 6 to 8 times faster than now. Previous
studies put the peak 8 billion years ago.

Heavens's team obtained a different result because it used a novel method for
determining the universe's star-formation history....

http://SkyandTelescope.com/news/article_1235_1.asp

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HIGHLIGHTS OF THIS WEEK'S SKY

* Last-quarter Moon on Sunday, April 11th.
* On April 13th, there is a double shadow transit on Jupiter! Two of Jupiter's
moons, Io and Europa, will both be casting their tiny black shadows onto the
planet's face from 3:31 to 4:04 a.m. Eastern Daylight Time that morning.
* Venus is the brilliant white "Evening Star" blazing grandly in the west
during twilight and much of the evening.

For details, see This Week's Sky at a Glance and Planet Roundup:

http://SkyandTelescope.com/observing/ataglance/

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NIGHT SKY MAGAZINE (Advertisement)

This new bimonthly magazine has been designed especially for entry-level
observers who want to enjoy and explore the stars. With its clear, nontechnical
writing and helpful tips, you'll be star-hopping across the heavens in no time!

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Copyright 2004 Sky Publishing Corp. S&T's Weekly News Bulletin is provided as a
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*-----------------------------------------------------*
| Stuart Goldman |
* Associate Editor *
| Sky & Telescope |
* 49 Bay State Rd. Sky & Telescope: The Essential *
| Cambridge, MA 02138 Magazine of Astronomy |
*-----------------------------------------------------*

In message , Stuart
Goldman writes

BUILDING PLANETS IN PLASTIC BAGS

Last year astronaut Donald R. Pettit (NASA/Johnson Space Center) was aboard the
International Space Station preparing his weekly Saturday Morning Science
program, in which he performed various experiments highlighting the fun things
one can do in microgravity. Before him were plastic bags containing salt,
sugar, and coffee grounds. The demonstration he had planned that morning was
fairly mundane -- shake the bags and watch what happens. Little did Pettit know
he might be about to solve experimentally one of most perplexing paradoxes
surrounding the formation of planets.

For decades theorists have had trouble growing planets starting from small dust
grains in a protoplanetary gas-and-dust disk. Given a turbulent disk
environment with high winds and high-velocity (100 meters/second) impacts
between objects, small, millimeter-size clumps should have difficulty growing
to centimeter size and larger without breaking back into millimeter fragments.
No one had ever seen it work experimentally.

Pettit proceeded to take the bags of particles and shake them in front of the
camera....

http://SkyandTelescope.com/news/article_1236_1.asp

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

HUBBLE SERVICING: ROBOT TO THE RESCUE?

While astronomers and politicians continue to debate NASA's decision to cancel
further shuttle missions to the Hubble Space Telescope, engineers are looking
for other ways to keep the orbiting observatory alive as long as possible.
Already they're changing how they operate the telescope to circumvent or delay
inevitable hardware failures. And they're looking at the possibility of
dispatching an advanced robot to perform some, if not all, of the servicing
tasks that were originally to be carried out by space-walking astronauts....

http://SkyandTelescope.com/news/article_1233_1.asp

Does anyone else think the development of this technology will be very
bad news for manned spaceflight enthusiasts?
One of the very few justifications for the Shuttle was HST servicing
missions, and "fun things one can do in microgravity" don't justify $100
billion budgets.
--
Save the Hubble Space Telescope!
Remove spam and invalid from address to reply.