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07/06/2018 – Ephemeris – Learn about meteorites tonight

July 6, 2018 Comments off

Ephemeris for Friday, July 6th. Today the Sun will be up for 15 hours and 26 minutes, setting at 9:30, and it will rise tomorrow at 6:04. The Moon, at last quarter today, will rise at 2:06 tomorrow morning.

Meteorites will be the topic given by Joe Brooks local meteorite expert and collector at this evening’s meeting of the Grand Traverse Astronomical Society at 8 p.m. at Northwestern Michigan College’s Rogers Observatory. He even has a meteorite of a type called a Howardite that the Dawn spacecraft that orbited the asteroid Vesta has determined to be from the there. Today we are all too aware that stones and even bigger asteroids can collide with the Earth, so studying meteorites and the asteroids they come from is important. Everyone is welcome. Also at 9 p.m. there will be a star party at the observatory. The observatory is located south of Traverse City on Birmley Road between Garfield and Keystone roads.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

A Howardite meteorite is a chip off this old block.

Vesta as Dawn headed off to Ceres.

Looking back at Vesta as Dawn headed off to Ceres. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA

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01/29/2018 – Ephemeris – Michigan fireball

January 29, 2018 1 comment

Ephemeris for Monday, January 29th. The Sun will rise at 8:05. It’ll be up for 9 hours and 42 minutes, setting at 5:47. The Moon, 2 days before full, will set at 7:13 tomorrow morning.

The meteoroid that exploded over southern Michigan nearly two weeks ago was seen by many people, mostly in the southeastern Michigan though some reports were from around here. The explosion, high in the atmosphere registered 2.0 on an earthquake recording seismograph in Ann Arbor. That was just from the pressure wave. Pieces of meteorites from it have been found laying on the snow. It appears to have been a normal stony meteoroid. The strewn field where the meteorites have been found is in Hamburg township, southwest of Brighton. The meteoroid came in at 28,000 miles per hour (45,000 kph), a lot slower than a Perseid meteoroid. Rule of thumb for the nomenclature of these things: meteoroid, before; meteor, the light in the sky, meteorite, what’s left that hits the ground.  Unfortunately, I didn’t see it.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Meteor observer map

A map of the location of observers of the fireball. Map credit Google & American Meteor Society.

Meteorite fragmnet

A piece of the meteorite found in the strewn field southwest of Brighton, MI. It appears to be a low iron chondrite, a common rocky meteorite. Credit Mike Hankey / American Meteor Society.

Here’s a Sky and Telescope post about the event: http://www.skyandtelescope.com/astronomy-news/observing-news/michigan-fireball/

04/03/2015 – Ephemeris – Learn about meteorites tonight

April 3, 2015 Comments off

Ephemeris for Good Friday, Friday, April 3rd.  The Sun will rise at 7:20.  It’ll be up for 12 hours and 52 minutes, setting at 8:12.   The Moon, 1 day before full, will set at 7:24 tomorrow morning.

Meteorites will be the topic given by Joe Brooks local meteorite expert and collector at this evening’s meeting of the Grand Traverse Astronomical Society at 8 p.m. at Northwestern Michigan College’s Rogers Observatory.  He even has a meteorite that’s pretty much been proven to be from the asteroid Vesta.  Today we are all too aware that stones and even bigger asteroids can collide with the earth.    Everyone is welcome.  Also at 9 p.m. there will be a star party at the observatory.  The observatory is located south of Traverse City on Birmley Road between Garfield and Keystone roads.  Remember also the partial lunar eclipse tomorrow morning starting at 6:15 a.m.  The society and the observatory will not hold an event for it.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

If you missed yesterday’s post about tomorrow morning’s lunar eclipse, click here.

03/30/2015 – Ephemeris – The importance of meteorites and asteroids

March 30, 2015 Comments off

Ephemeris for Monday, March 30th.  The Sun will rise at 7:27.  It’ll be up for 12 hours and 39 minutes, setting at 8:07.   The Moon, 3 days past first quarter, will set at 5:33 tomorrow morning.

On Friday the 3rd Joe Brooks will be giving a talk at the Grand Traverse Astronomical Society on meteorites.  That will be at 8 p.m. at Northwestern Michigan College’s Rogers Observatory.  NASA has the Dawn spacecraft now settling into orbit of the largest asteroid Ceres.  It is the asteroid belt that is the source of meteorites.  Meteorites are either pieces of destroyed protoplanets due to collisions in the asteroid belt or primitive objects like carbonaceous chondrites pristine that date back to 4.567 billion years ago, the formation of the solar system.  Meteorites tend to be contaminated by the environment.  That’s why samples of asteroids will be so valuable for planetary defense and understanding the origin of the solar system.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Vesta as Dawn headed off to Ceres.

Looking back at Vesta as Dawn headed off to Ceres. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA

Ceres 2/19/15

The bright spot is two. Picture taken February 19, 2015 from 29,000 miles (46,700 km). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.