Get Ready Stargazers: The Geminids Are Coming!

The second week of December heralds the beginning of the strongest meteor shower of the year – the Geminids. It’s a good time to bundle up, go outside and watch one of Mother Nature’s best sky shows!

The Geminids are active every December, when Earth passes through a massive trail of dusty debris shed by a weird, rocky object named 3200 Phaethon. The dust and grit burn up when they run into Earth’s atmosphere in a flurry of “shooting stars.”

Phaethon’s nature is debated. It’s either a near-Earth asteroid or an extinct comet, sometimes called a rock comet. There is another object – an Apollo asteroid named 2005 UD – that is in a dynamically similar orbit to Phaethon, prompting speculation that the two were once part of a larger body that split apart or collided with another asteroid.

Most shower meteors are shed by comets when their orbits take them into the inner Solar System, but the Geminids may be the debris from this long-ago breakup or collision event. When you consider that the Geminid meteor stream has more mass than any other meteor shower, including the Perseids, whatever happened back then must have been pretty spectacular.

So what do potential Geminid watchers need to do this year?

It’s pretty simple, actually. The nearly First Quarter Moon sets around 10:30 p.m. local time, so wait until then to go out – the light from the Moon washes out the fainter meteors, which are more numerous. Find the darkest place you can, and give your eyes about 30 minutes to adapt to the dark. Avoid looking at your cell phone, as it will mess up your night vision. Lie flat on your back and look straight up, taking in as much sky as possible. You will soon start to see Geminid meteors. As the night progresses, the Geminid rate will increase, hitting a theoretical maximum of about 100 per hour around 2 a.m.

Bear in mind, this rate is for a perfect observer under perfect skies with Gemini straight overhead. The actual number for folks out in the dark countryside will be slightly more than 1 per minute. Folks in suburbs will see fewer, 30 to 40 per hour depending on the lighting conditions. And those downtown in major cities will see practically nothing – even though the Geminids are rich in beautiful green fireballs, the lights of New York, San Francisco, or Atlanta will blot even them out. Dark clear skies are the most important ingredient in observing meteor showers.

Comet Wirtanen has a light blue hue in this image taken by NASA astronomer Bill Cooke using an iTelescope widefield 90 mm refractor and color CCD camera Nov. 29 at Siding Spring Observatory in Australia.

And while you’re scanning the sky for Geminids, you might notice a small, faint “ghostly” green patch in the constellation of Taurus – that’s Comet 46P/Wirtanen, which will be making its closest approach to Earth (7 million miles) for the next 20 years. We are actually going to have a comet visible to the unaided eye this holiday season!

Graphic showing the locations of the Geminid radiant and Comet 46P/Wirtanen for 35 degrees north latitude at 10:30 p.m. on the night of the Geminid peak (December 13).

Comets are notoriously unpredictable beasts, but if Wirtanen continues to follow its current brightening trend, it may reach a peak magnitude of around +3 (about as bright as a star in the handle of the Little Dipper) a couple of days past the Geminid peak, on December 16. Binoculars or a small telescope are good for taking a peak at Wirtanen, so bring them along for your night of Geminid watching. A green comet to compliment the green fireballs!

Bright Fireball Spotted Over Michigan

A bright fireball lit up skies over Michigan at 8:08 p.m. EST on Jan. 16, an event that was witnessed and reported by hundreds of observers, many who captured video of the bright flash.

Based on the latest data, the extremely bright streak of light in the sky was caused by a six-foot-wide space rock — a small asteroid. It entered Earth’s atmosphere somewhere over southeast Michigan at an estimated 36,000 mph and exploded in the sky with the force of about 10 tons of TNT. The blast wave felt at ground level was equivalent to a 2.0 magnitude earthquake.

The fireball was so bright that it was seen through clouds by our meteor camera located at Oberlin college in Ohio, about 120 miles away.

Events this size aren’t much of a concern. For comparison, the blast caused by an asteroid estimated to be around 65 feet across entering over Chelyabinsk, Russia, was equivalent to an explosion of about 500,000 tons of TNT and shattered windows in six towns and cities in 2013. Meteorites produced by fireballs like this have been known to damage house roofs and cars, but there has never been an instance of someone being killed by a falling meteorite in recorded history.

The Earth intercepts around 100 tons of meteoritic material each day, the vast majority are tiny particles a millimeter in diameter or smaller. These particles produce meteors are that are too faint to be seen in the daylight and often go unnoticed at night. Events like the one over Michigan are caused by a much rarer, meter-sized object. About 10 of these are seen over North America per year, and they often produce meteorites.

There are more than 400 eyewitness reports of the Jan. 16 meteor, primarily coming from Michigan. Reports also came from people in nearby states and Ontario, Canada, according to the American Meteor Society. Based on these accounts, we know that the fireball started about 60 miles above Highway 23 north of Brighton and travelled a little north of west towards Howell, breaking apart at an altitude of 15 miles. Doppler weather radar picked up the fragments as they fell through the lower parts of the atmosphere, landing in the fields between the township of Hamburg and Lakeland. One of the unusual things about this meteor is that it followed a nearly straight-down trajectory, with the entry angle being just 21 degrees off vertical. Normally, meteors follow a much more shallow trajectory and have a longer ground track as a result.

Shows the trajectory of the meteor.
This image shows the trajectory of the meteor as determined by the eyewitness accounts posted on the American Meteor Society Website. It is likely that there are meteorites on the ground near this region. (American Meteor Society)

NASA’s Short-term Prediction Research and Transition Center reported that a space-based lightning detector called the Geostationary Lightning Mapper — “GLM” for short — observed the bright meteor from its location approximately 22,300 miles above Earth. The SPoRT team helps organizations like the National Weather Service use unique Earth observations to improve short-term forecasts.

GLM is an instrument on NOAA’s GOES-16 spacecraft, one of the nation’s most advanced geostationary weather satellites. Geostationary satellites circle Earth at the same speed our planet is turning, which lets them stay in a fixed position in the sky. In fact, GOES is short for Geostationary Operational Environmental Satellite. GLM detected the bright light from the fireball and located its exact position within minutes. The timely data quickly backed-up eyewitness reports, seismic data, Doppler radar, and infrasound detections of this event.

Data from NOAA's GOES-16 space-based weather satellite
Data from NOAA’s GOES-16 space-based weather satellite detected a bright flash of light over southeast Michigan around the time a meteor entered Earth’s atmosphere. (NASA/SPoRT)

Much like the nation’s weather satellites help us make decisions that protect people and property on Earth, NASA’s Meteoroid Environment Office watches the skies to understand the meteoroid environment and the risks it poses to astronauts and spacecraft, which do not have the protection of Earth’s atmosphere. We also keep an eye out for bright meteors, so that we can help people understand that “bright light in the night sky.”

Comet Lovejoy – January 2015

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

NASA Experts Discuss Russia Meteor in Media Teleconference Today

NASA experts will hold a teleconference for news media at 4 p.m. EST today to discuss a meteor that streaked through the skies over Russia’s Urals region this morning.

Scientists have determined the Russia meteor is not related to asteroid 2012 DA14 that will pass safely pass Earth today at a distance of more than 17,000 miles. Early assessments of the Russia meteor indicate it was about one-third the size of 2012 DA14 and traveling in a different direction.

Panelists for the teleconference are:

— Bill Cooke, lead for the Meteoroid Environments Office at NASA’s Marshall Space Flight Center in Huntsville, Ala.
— Paul Chodas, research scientist in the Near Earth Object Program Office at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

The teleconference will be carried live online at:

https://www.nasa.gov/newsaudio

For detailed information concerning the Earth flyby of 2012 DA14, visit:

https://www.nasa.gov/topics/solarsystem/features/asteroidflyby.html

The Upcoming Asteroid Flyby — Can I See It?

This is the most common question we are asked, and the answer is “maybe.” It all depends on where you are located and what sort of equipment you have.
 
Closest approach will be around 19:25 UTC on February 15; this will be when the asteroid will be at its brightest. Even at this time, when 2012 DA14 is only about 17,000 miles above Earth’s surface, it will not be visible to the unaided eye due to its small size. Observers in Indonesia (which is favored to see close approach) will need binoculars to catch a glimpse of the asteroid as it moves rapidly through the sky.
 
The rest of us will need to use a telescope. In North America, 2012 DA14 will be no brighter than magnitude 11 when the Sun sets on the 15th. This is over 60 times fainter than the faintest star you can see with your eyes under perfect sky conditions. Also, it will still be moving quickly through the constellations — over 3 degrees (6 Moon diameters) per hour — and this speed, combined with its fading, will make it a challenging target, even for experienced amateurs. Algorithms in many of the software programs used to drive telescopes are not suited for fast movers like this one, and may point the telescope in the wrong locations (A test we conducted using a popular software package showed that it would point the telescope over a degree away from the actual position of DA14, well outside the one half degree field of view of most instruments). So seeing 2012 DA14 before it fades beyond the limit of most amateur telescopes will not be a simple task; it will require some thought and advanced planning. An invaluable tool in planning your observations is the JPL Horizons website (http://ssd.jpl.nasa.gov), which can calculate the precise positions of 2012 DA14 for your location.
 
So can I see 2012 DA 14? The answer is yes — if you have access to a decent telescope, if you take the time to figure out where you need to look in advance, and if your sky is clear. A lot of work, but the reward is a glimpse of a house-size visitor from another part of the Solar System as it whizzes by our planet at a distance closer than many of the communications satellites we depend upon in our daily lives. A rare event, to be sure.
 
Those without telescope access may also get a glimpse. NASA will be streaming the latter part of the asteroid flyby on Ustream at http://www.ustream.tv/channel/nasa-msfc – if the skies are clear in Alabama and the MSFC-based telescope can view DA14, you can use the Internet to get a peek at 2012 DA14 (which will look like a fast moving star) from the comfort of your home.

 

Rare Double Quadrantid Meteor Sighting


The wide-field meteor camera at NASA’s Marshall Space Flight Center recorded these two simultaneous Quadrantid meteors on Jan. 4 at approximately 5 a.m. EST. Moving at 92,000 mph, the meteors flashed across the field of view in just over a second.


 



Credits: NASA/MSFC/Meteoroid Environments Office

Slow-Moving Meteor Paints the Night Skies

Early on the morning of Jan. 3, 2012, a beautiful meteor was seen traveling across the skies over Huntsville, Ala. Moving slowly at “only” 18.9 km/s — or 42,000 mph — the meteor was recorded at approximately 10:34:16 UTC in an allsky camera at the Marshall Space Flight Center. It started 88.5 km/55 miles up and was last detected at 79.8 km/50 miles up. The meteor had a mass of 22 grams and was about an inch in diameter — fairly big for a meteor — and its orbit went out to the asteroid belt.

The view below shows the meteor’s path captured by an allsky color camera, also located at the Marshall Center.

Image credits: NASA/MSFC/Meteoroid Environments Office/Bill Cooke and Danielle Moser

Geminid Over Las Cruces

Hazy skies did little to dim the brightness of this Gemind meteor, which graced the skies over southern New Mexico on the night of Dec. 14 around 7:28 p.m. MST. Moving at 80,000 mph, the 3/4 inch meteor — a piece of the asteroid 3200 Phaethon — flared brighter than the planet Venus before burning up 47 miles above the U.S./Mexico border.

Image credit: Marshall Space Flight Center, Meteoroid Environments Office, Bill Cooke