Tag Archives: Meteoroid Environment Office

NASA Marshall to Host Ustream Event About Perseid Meteor Shower August 12; Experts to Answer Questions Online

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Perseid Meteor Shower Banner

Enjoy a summer evening of sky watching as the annual Perseid meteor shower peaks on the night of August 12 through the morning of August 13. Join meteor experts from NASA’s Marshall Space Flight Center for live Ustream commentary during the shower. Perseid meteor rates can get as high as 100 per hour, with many fireballs visible in the night sky

How to View the Perseid meteor shower

The best opportunity to see the Perseid meteor shower is during the dark, pre-dawn hours of August 13. The Perseidss streak across the sky from many directions. For optimal viewing, find an open skyline, where you can view the horizon without obstructions, such as buildings or trees.  Try to view the Perseids as far away from artificial lights as possible. The darker the sky, the better viewing experience you can have. Lie on the ground and look straight up. Remember, your eyes can take up to 30 minutes to adjust to the darkness, so allow plenty of time for your eyes to adjust.

About the Perseids

The Perseids have been observed for at least 2,000 years and are associated with the comet Swift-Tuttle, which orbits the sun once every 133 years. Every August, the Earth passes through a cloud of the comet’s debris. This debris field consists of bits of ice and dust — most over 1,000 years old — and burns up in Earth’s atmosphere to create one of the best meteor showers of the year. The Perseids can be seen all over the sky, but the best viewing opportunities will be across the northern hemisphere. Those with sharp eyes will see that the meteors radiate from the direction of the constellation Perseus.

NASA Ustream: Observe the Perseid Meteor Shower

On Aug. 12, NASA’s Marshall Space Flight Center in Huntsville, Alabama, will host a live Ustream broadcast about the Perseid meteor shower. The event will highlight the science behind the Perseids, as well as NASA research related to meteors and comets. The broadcast will air 9 p.m. CDT Aug. 12, to 1 a.m. CDT Aug. 13 on the following Ustream channel: http://www.ustream.tv/channel/nasa-msfc

Special guests will include meteor experts Dr. Bill Cooke, Danielle Moser and Rhiannon Blaauw, all of NASA’s Micrometeoroid Office, located at Marshall. They will provide on-air commentary, as well as answer questions online, using Marshall social media accounts. Also scheduled to join the broadcast, via telephone, are experts from NASA’s Johnson Space Center, in Houston; NASA’s Goddard Space Flight Center in Greenbelt, Maryland; the American Meteor Society; the SETI Institute in Mountain View, California; and others.

There are two methods to join the online conversation during the broadcast. NASA followers can tweet questions to “@NASA_Marshall” using the hashtag “#askNASA.” Followers may also post questions on the Marshall Facebook account, replying to the 9 p.m. Aug. 12 Perseid “Q&A” post at: https://www.facebook.com/nasamarshallcenter

Comet Lovejoy – January 2015

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Image of Comet Lovejoy taken Saturday, January 10, by Dr. Bill Cooke. Image is a 3 minute exposure using the iTelescope T3 refractor. At the time of this image, the comet was some 45 million miles from Earth.

Discovered in August of 2014, Comet Lovejoy is currently sweeping north through the constellation Taurus, bright enough to offer good binocular views. Glowing softly with a greenish hue, Comet Lovejoy passed closest to planet Earth on January 7, while its perihelion (closest point to the Sun) will be on January 30. Classed as a long period comet, it should return again … in about 8,000 years.

LoveJoyView more images of Comets at our Flickr Gallery

Sunday Night Fireball

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On Sunday evening, a bright fireball was reported by visual observers in Tennessee. Occurring about 7:22 PM Central, the meteor was detected by 4 of our All Sky cameras – those in Huntsville; Chickamauga, GA; Cartersville, GA; and Dahlonega, GA. The fireball was picked up at an altitude of 55 miles moving east of south at 52,000 miles per hour; it burned up at an altitude of 27 miles just south of Anniston, AL. This was not a Taurid, as the orbit indicates it is a fragment from a Jupiter family comet, which have an aphelion (furthest distance from the Sun) out near Jupiter. This particular piece of interplanetary debris was between 2-3 inches in diameter and weighed about 5 ounces.

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Geminids: How Low Do They Go?

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The Marshall Meteoroid Environment office put together the plot below showing the distribution of end heights of Geminids seen with our fireball camera network. 85% of Geminids burn up 40 to 55 miles above Earth’s surface and 15% get below 40 miles altitude.
 
Geminids penetrate deeper into the atmosphere than the Perseids because they are moving slower (78,000 mph for the Geminids compared to 130,000 mph for the Perseids) and are made up of denser material, owing to the fact that the Geminid parent body is rocky asteroid 3200 Phaethon and the Perseid parent is a comet yielding more fragile material.
 

This video shows meteors captured by a wide-field camera at the NASA Marshall Space Flight Center on the night of December 12. There are 141 events; at least 77 of these are Geminids, based on their angular speed and direction of travel. Near the end of the movie, a couple of satellites are visible crossing the field of view.

For those of us sky watching for meteors , this means we have a good chance of viewing a Geminid meteor. Tonight, December 13, into the early morning of December 14 is the peak. Happy meteor watching!

NASA Cameras Catch Speeding Fireball

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There was a bright fireball visible over north Georgia, eastern Tennessee, and South Carolina at 7:02:36 PM EST last night. All 4 NASA meteor cameras in the SouthEast picked it up 48 miles above the town of Rossville, just south of Chattanooga, moving at 9 miles per second (32,400 mph) slightly north of east. The meteor appears to have ablated (“burned up”) at 23 miles altitude SW of of Ocoee, TN. Though unusual, it is unlikely that this object produced any noticeable meteorites on the ground.

Orbit indicates that this meteor was asteroidal in origin, with an aphelion (farthest point from the Sun) in the main asteroid belt between Mars and Jupiter.

 

 

Asteroid 433 Eros Approaches Earth

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Credit:  NASA/MSFC/Meteoroid Environment Office/Rhiannon Blaauw

Asteroid 433 Eros made a close approach to Earth the morning of January 31st coming within 0.17 AU (15 million miles) of our planet. In this set of images taken that morning, the bright moving dot near the center of the field is the 21 mile long Eros. Somewhere on that tiny point of light rests a United States spacecraft — Near Shoemaker — which touched down on the asteroid’s surface on February 12, 2001 after completing 230 orbits around Eros.
 
In the animation you will also notice over 20 streaks of light moving almost horizontally across the field of view. What we did not realize at the time of imaging was that Eros was at approximately the declination of geosynchronous communication satellites! These satellites are orbiting some 22,236 miles above the earth in the “Clark belt.” We were able to identify most of the satellites seen and found quite a variety.

Included in the video are Brazilian satellites (Brazilsat B2, Star One C2); American satellites (Galaxy 11); Canadian satellites (Nimiq 4, Anik F1); Venezuelan satellites (Venesat-1); weather satellites (GEOS 12); television satellites (DirecTV 1-R); radio satellites (XM 3, Sirius FM); and Internet satellites (WildBlue – 1).

A Shadow on the Moon

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The next full moon is known as the Cold Moon, the Long Night Moon, or the Moon Before Yule. The moon will be “opposite” the sun at 9:38 a.m. EST on Saturday, Dec. 10. The moon will appear full for about three days around this time, from the evening of Thursday, Dec. 8 through the morning — and possibly the evening — of Sunday, Dec. 11.

On Dec.10, the moon will be so “opposite” the sun from the Earth that it will pass through the shadow of the Earth. The Earth’s shadow will begin to reduce the amount of sunlight reaching the moon at about 6:34 a.m. EST, but the U.S. East Coast will not be able to tell that the moon appears dimmer before it sets at 7:08 a.m. EST. The full shadow of the Earth (called the umbra) does not start to fall on the moon until about 7:46 a.m. EST, well after the moon has set for the U.S. East Coast. Even for the U.S. West Coast, the eclipse will be near moonset, making this a difficult eclipse to view. The extended period with reduced sunlight, including 51 minutes in the full shadow of the Earth, presents a challenging environment for spacecraft at the moon (LRO, the twin GRAIL spacecraft) that rely upon sunlight for heat and solar power. Because the two ARTEMIS spacecraft are in highly elliptical orbits around the moon, it is not clear if or how they will be impacted.

Europeans call the December full moon the Moon before Yule. Yule is an old northern European winter festival that is now associated with Christmas. The Native American names for the full moon in December — as reported in the Farmer’s Almanac — are the Cold Moon or the Long Night Moon. The Cold Moon gets its name because December is the month when it really starts to get cold, although our coldest average temperatures are in January. The Long Night Moon gets its name because the full moon in December occurs near the solstice, which has the longest night of the year. The full moon takes a high trajectory across the sky because it is opposite to the low sun, so the moon will be above the horizon longer than at other times of the year.


A full moon over Earth, seen by astronaut Ron Garan from the International Space Station. (NASA)

A Shadow on the Moon

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The next full moon is known as the Cold Moon, the Long Night Moon, or the Moon Before Yule. The moon will be “opposite” the sun at 9:38 a.m. EST on Saturday, Dec. 10. The moon will appear full for about three days around this time, from the evening of Thursday, Dec. 8 through the morning — and possibly the evening — of Sunday, Dec. 11.

On Dec.10, the moon will be so “opposite” the sun from the Earth that it will pass through the shadow of the Earth. The Earth’s shadow will begin to reduce the amount of sunlight reaching the moon at about 6:34 a.m. EST, but the U.S. East Coast will not be able to tell that the moon appears dimmer before it sets at 7:08 a.m. EST. The full shadow of the Earth (called the umbra) does not start to fall on the moon until about 7:46 a.m. EST, well after the moon has set for the U.S. East Coast. Even for the U.S. West Coast, the eclipse will be near moonset, making this a difficult eclipse to view. The extended period with reduced sunlight, including 51 minutes in the full shadow of the Earth, presents a challenging environment for spacecraft at the moon (LRO, the twin GRAIL spacecraft) that rely upon sunlight for heat and solar power. Because the two ARTEMIS spacecraft are in highly elliptical orbits around the moon, it is not clear if or how they will be impacted.

Europeans call the December full moon the Moon before Yule. Yule is an old northern European winter festival that is now associated with Christmas. The Native American names for the full moon in December — as reported in the Farmer’s Almanac — are the Cold Moon or the Long Night Moon. The Cold Moon gets its name because December is the month when it really starts to get cold, although our coldest average temperatures are in January. The Long Night Moon gets its name because the full moon in December occurs near the solstice, which has the longest night of the year. The full moon takes a high trajectory across the sky because it is opposite to the low sun, so the moon will be above the horizon longer than at other times of the year.


 A full moon over Earth, seen by astronaut Ron Garan from the International Space Station. (NASA)

Images of Rare Aurora in Southern Tennessee

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The colors of emitted light within an aurora depend on the initial energy of the charged particles (mostly electrons) cascading into Earth’s atmosphere.  Electrons with higher initial energies are able to penetrate deeper into the atmosphere, whereas those with lower initial energies lose all their energy at higher altitudes. The blue aurora emitted from low-altitude molecular nitrogen is most commonly seen at higher latitudes, such as in Canada and Alaska, where high-energy electrons are more common. Red aurorae mostly result from lower-energy electrons reacting with atomic oxygen at high altitudes, which can occur at lower latitudes (<50 degrees) during extremely strong geomagnetic storms — such as is seen in images here.  The auroral electrons that make it into the low-latitude atmosphere usually do not have enough energy to reach molecular nitrogen.  This is why low-latitude aurorae are almost always red.


Credit: Jeremy Myers, NASA Marshall Engineer
 

One Night, Five Meteor Showers

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On the night of Oct. 15-16, NASA’s All-sky camera network saw meteors from five different meteor showers! October is known to be a busy month in the world of meteor showers, but even five is an unusually high number.


 


 The last meteor seen in the early morning skies over Huntsville, Ala., on the night of the Oct. 15-16.

 

To see videos of these meteors, and others, go to fireballs.ndc.nasa.gov and select 20111016 on the left panel. In addition to those five shower meteors, eight sporadic or background  meteors were detected. The five showers were: Delta Aurigids, or DAU, October Ursa Majorids, or OCU, Chi Taurids, or CTA, Orionids , or ORI, and Eta Geminids, or EGE. See the list at the end of this post for more information on each shower.

 

The only shower mentioned above that would be worth observing for yourself is the Orionids. The Orionids peak this Friday evening — the night of Oct. 21-22 — and are best viewed anytime after midnight. They are one of the last showers of the year that may have favorable weather to lie outside all night. If you are in Northern Alabama, October evenings are still quite pleasant for stargazing. Luckily for you the moon won’t be too much of a problem. Only a small fraction of the moon is illuminated, unlike many major meteor showers this year whose rates were considerably hampered because the light from a full moon washed them out.

 

Delta Aurigids, or DAU: Active from Sept. 20 — Oct. 16, peaking on Oct. 3 with only two meteors per hour. Velocity of 143,000 miles/hour. The Delta Aurigids are not a well-known shower thus any observations refine the information we know about them.

 

October Ursa Majorids, or OCU: Active from Oct. 12-19, peaking on Oct. 15. Velocity of 119 miles/hour. This is a very minor shower rates of less than one per hour. Radiant — where the meteors appear to come from — is in Ursa Major.

 

Chi Taurids, or CTA:  Active from Oct. 10 — Nov. 10, peaking on Nov. 3. Velocity approximately 94,000 miles/hour. This is also a shower that has very little known about it. It was recently discovered in a survey to find minor meteor showers using a meteor radar (Brown et al, 2010).

 

Orionids, or ORI: Active from Oct. 2 — Nov. 7, peaking on Oct. 21 with rates up to 25 per hour. Velocity of 150,000 miles/hour. Radiant is in the constellation Orion.

 

Eta Geminids, or EGE:  Active from Oct. 14-27.  Peaking on Oct. 18 with rates of three per hour. These are fast-moving meteors that average at 157,000 miles/hour. Eta Geminids are often confused with Orionids since their velocity and peaks are similar.

 

Brown, P., Wong, D.K., Weryk, R.J., Wiegert, P.

A meteoroid stream survey using the Canadian Meteor Orbit Radar II: Identification of minor showers using a 3D wavelet transform

Icarus 207 (2010) 66–81.

 

 

Credits: NASA/MSFC/Meteoroid Environment Office/Rhiannon Blaauw, Bill Cooke

 

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