[meteorite-list] Spaceships, Meteors, and Moonlight

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 10 Aug 2011 10:32:31 -0700 (PDT)
Message-ID: <201108101732.p7AHWV2i022295_at_zagami.jpl.nasa.gov>

http://science.nasa.gov/science-news/science-at-nasa/2011/09aug_perseids2011/

Spaceships, Meteors, and Moonlight
NASA Science News
August 9, 2011

Bright moonlight streams through your window. A nugget
of space debris disintegrates in a sparkling fireball. A huge spaceship
glides silently overhead.

By itself, any one of these events might be enough to get you out of
bed. This weekend, all three are going to happen at the same time.

On August 12th and 13th, as the Moon waxes full, the International Space
Station will glide over US towns and cities during the peak of the
annual Perseid meteor shower.

The meteor shower is already underway. Earth is passing through a broad
stream of debris from Comet Swift-Tuttle, and specks of comet dust are
hitting the top of Earth's atmosphere at 140,000 mph. These
disintegrating meteors stream out of the constellation Perseus--hence
the name "Perseids." According to the International Meteor Organization,
worldwide observers now are counting more than a dozen Perseids per hour
with more to come on August 12-13 when Earth passes near the heart of
the debris stream.

Experts note that moonlight and meteor showers don't mix. Indeed, the
great number of faint Perseids that observers would normally count in a
dark year will be invisible in 2011 with the Moon glaring overhead. On
the bright side--no pun intended--any Perseid that does manage to pierce
the glare is likely to be a fireball. These are caused by relatively big
pieces of debris disintegrating in flashes too bright to be subdued.
It's not unusual to see at least a few Perseid shadow-casters on peak
night.

Perseid meteors can appear any time Perseus is above the horizon--i.e.,
between about 10 pm and sunrise. The best time to look is during the
hours before dawn especially on Saturday morning, August 13th. The full
Moon will be relatively low, and the meteor rate should be peaking at
that time.

Before dawn is also the time of the ISS. All week long and into the
weekend, the International Space Station will be making a series of
early-morning flybys over the United States. The massive spacecraft
glides silently among the stars, shining so brightly that moonlight and
even city lights have little affect on its visibility. You simply cannot
miss it if you know when to look. Check NASA's ISS Tracker
<http://spaceflight.nasa.gov/realdata/sightings/index.html> for local
flyby times. Several major cities are favored with flybys on August 12th
and 13th including Chicago, Dallas, Denver, Los Angeles, New York and
others.

Set your alarm and enjoy the show.


Author: Dr. Tony Phillips
Credit: Science at NASA
Received on Wed 10 Aug 2011 01:32:31 PM PDT