[Prev][Next][Index][Thread]
(meteorobs) Excerpt from "CCNet, 28 October 1999"
This item was VERY interesting (and on-topic)! Was anyone on our list
aware of Dr. Drummond's research - or of this amateur observer Kevin
McKeown? Or for that matter that Dave Crawford (of IDA fame) had had
any interest in or knowledge about meteor science??
Inquiring minds want to know. :)
Lew Gramer
------- Forwarded Message
From: Benny J Peiser <b.j.peiser@livjm.acdot uk>
To: cambridge-conference@livjm.acdot uk
Subject: CCNet, 28 October 1999
Date: Thu, 28 Oct 1999 09:51:03 -0400 (EDT)
CCNet, 28 October 1999
======================
[...]
(4) MYSTERY FOLLOWS METEORS
Andrew Yee <ayee@nova.astro.utorontodot ca>
[...]
=================================================
(4) MYSTERY FOLLOWS METEORS
>From Andrew Yee <ayee@nova.astro.utorontodot ca>
[http://www.abqjournal.com/scitech/1sci10-26-99.htm]
Tuesday, October 26, 1999=20
Mystery Follows Meteors
By John Fleck, Albuquerque Journal Staff Writer
Astronomers chasing rare and mysterious "glowworms in the sky" that=20
swarm every 33 years or so will converge on Albuquerque next month.
The occasion is the annual Leonid meteor shower, an every-November=20
light show in the night sky that once every 33 years turns into an=20
extravaganza of shooting stars.
This year's show is expected to be a doozy.
That's a problem for satellite operators, a treat for stargazers and=20
a potential scientific bonanza for Air Force astronomer Jack Drummond=20
and his colleagues.
They're trying to understand how little grains of dust and sand=20
slamming into Earth's atmosphere can leave twisting, billowing,=20
glowing trails that sometimes last for hours.
The trails, which Drummond calls "glowworms in the sky," were first=20
noticed in 1833, but they've never been explained, Drummond said.
Last year, the scientists used a modest Leonid show to study a=20
handful of glowworms, armed with a telescope and lasers at an Air=20
Force observatory on a hilltop south of Albuquerque.
This year they'll be back in force, using a suite of special=20
instruments to try to pin down the cause of the strange glowing=20
trains.
The Leonids occur when Earth, on its orbit around the sun, passes
through the trail of dust left by a comet called Tempel-Tuttle, which
orbits the sun every 33 years.
The trail is always there, which is why we get Leonids every November.
But in 1998, Tempel-Tuttle passed near us, leaving a load of fresh=20
dust, which is why scientists expect a light show this year.
"Ninety-nine's the big year. I'm willing to make small bets -- not
big bets, but small bets," said Kevin McKeown, an Albuquerque amateur
astronomer and veteran meteor-watcher.
The storm of shooting stars is caused when grains of dust and sand
collide with Earth's atmosphere, explained Sandia National
Laboratories physicist Dave Crawford.
They might not be big, but their speed as they slam into Earth's
atmosphere is prodigious -- about 40 miles per second.
That pumps enough energy into the atmosphere to heat it so much that=20
electrons are stripped off of its molecules, creating the brief flash=20
of a meteor.
"That's really what you're seeing is glowing air," Crawford said.
But in some cases, there's more.
Some of the brightest meteors leave a more lasting luminous trail,=20
and therein lies the mystery Drummond and his colleagues are trying=20
to solve.
Drummond's "glowworms in the sky" were first recorded during a Leonid=20
shower in 1833, the scientist told reporters during a briefing=20
Monday.
According to McKeown, they are visible in other meteor showers but=20
most common during the especially bright and spectacular Leonids.
At their best, he said, they are "very easy naked-eye objects,"=20
requiring no telescope or binoculars to see.
Drummond and his colleagues used the Air Force's Starfire Optical=20
Range telescope on a Kirtland Air Force Base hilltop to study them=20
during last November's Leonid shower.
They shone a laser at it hoping to see the light reflected back. When=20
it wasn't, they knew the glowworm wasn't a smoky trail.
Instead, something in the trail itself, 50 miles high in the thinnest=20
part of the atmosphere, is generating its own light. But what?
This year, they aim to find out.
Three instruments called spectrographs, which split light into its=20
various colors, will be used.
Because different chemicals emit different colors of light, a=20
spectrograph can be used to determine the glowworms' chemical=20
composition.
The scientists will be training their instruments on the sky shortly
after midnight on the mornings of Nov. 17 through 19, hunting=20
glowworms.
And for members of the general public, it's also worth staying up=20
late, said McKeown. A dark spot out of town is best, but the Leonids=20
are likely to be bright enough that even in the glare of city lights=20
they should put on a show.
"You've got to go out and look," he said. "If you miss it, you'll=20
never be able to live with yourself."=20
Copyright =A9 1999 Albuquerque Journal
[NOTE: Images from the Starfire Optical Range experiment are
available at http://www.sor.plk.af.mil/Leonids.htm - A.Y.]
----------------------------------------
THE CAMBRIDGE-CONFERENCE NETWORK (CCNet)
----------------------------------------
The CCNet is a scholarly electronic network. To subscribe/unsubscribe,=20
please contact the moderator Benny J Peiser <b.j.peiser@livjm.acdot uk>.=20
Information circulated on this network is for scholarly and=20
educational use only. The attached information may not be copied or=20
reproduced for any other purposes without prior permission of the=20
copyright holders. The fully indexed archive of the CCNet, from=20
February 1997 on, can be found at:
http://abob.libs.ugadot edu/bobk/cccmenu.html
------- End of Forwarded Message
To UNSUBSCRIBE from the 'meteorobs' email list, use the Web form at:
http://www.tiacdot net/users/lewkaren/meteorobs/subscribe.html