Well over 100 people in California, Nevada, Arizona and Oregon observed a fireball at 5:35 p.m. PST Dec. 19. This event was unusual not for the brightness of the fireball—similar to that of a crescent Moon—but for the persistent train left behind after the object ablated. This persistent train lasted for minutes (compared to the one second duration of the fireball) and was caused by sunlight reflecting off dust particles left behind by the meteoroid as it broke apart in Earth’s atmosphere. Upper atmosphere winds distorted the train over time, giving it a curvy, “corkscrew” appearance.
An analysis of the eyewitness accounts indicates that the meteor first became visible at an altitude of 48 miles over the Pacific Ocean some 50 miles west of the entrance to San Francisco Bay. Moving west of south at 63,000 miles per hour, it managed to survive only a second or so before ablating and breaking apart at an altitude of 34 miles above the ocean.
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.
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!
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 complement the green fireballs!
A live broadcast of the meteor shower from a camera in Huntsville, AL (if our weather cooperates!) will be available on NASA TV and the NASA Meteor Watch Facebook starting around 9 p.m. Eastern time (8 p.m. CT) and continuing until the early hours of August 13.
The Perseid meteor shower is here! Perseid meteors, caused by debris left behind by the Comet Swift-Tuttle, began streaking across the skies in late July and will peak on August 12.
The Perseid meteor shower is often considered to be one of the best meteor showers of the year due to its high rates and pleasant late-summer temperatures. This year’s shower peak, however, has the added bonus of dark skies courtesy of an early-setting crescent Moon. Combine these ideal observing conditions and high rates (an average of 60 meteors per hour at the peak) with the fact that the best nights for viewing – August 11 to 12 and August 12 to 13 – occur on a weekend and you have a recipe for successfully viewing some celestial fireworks!
When Should I Look?
Make plans to stay up late or wake up early the nights of August 11 to 12 and August 12 to 13. The Perseids are best seen between about 2 a.m. your local time and dawn.
If those hours seem daunting, not to worry! You can go out after dark, around 9 p.m. local time, and see Perseids. Just know that you won’t see nearly as many as you would had you gone out during the early morning hours.
How can you see the Perseids if the weather doesn’t cooperate where you are? A live broadcast of the meteor shower from a camera in Huntsville, AL (if our weather cooperates!) will be available on the NASA Meteor Watch Facebook starting around 8 p.m. CT and continuing until the early hours of August 13. Meteor videos recorded by the NASA All Sky Fireball Network are also available each morning; to identify Perseids in these videos, look for events labeled “PER.”
Why Are They Called Perseids?
All meteors associated with one particular shower have similar orbits, and they all appear to come from the same place in the sky, called the radiant. Meteor showers take their name from the location of the radiant. The Perseid radiant is in the constellation Perseus. Similarly, the Geminid meteor shower, observed each December, is named for a radiant in the constellation Gemini.
How to Observe Perseids
If it’s not cloudy, pick an observing spot away from bright lights, lay on your back, and look up! You don’t need any special equipment to view the Perseids – just your eyes. (Note that telescopes or binoculars are not recommended.) Meteors can generally be seen all over the sky so don’t worry about looking in any particular direction.
While observing this month, not all of the meteors you’ll see belong to the Perseid meteor shower. Some are sporadic background meteors. And some are from other weaker showers also active right now, including the Alpha Capricornids, the Southern Delta Aquariids, and the Kappa Cygnids. How can you tell if you’ve seen a Perseid? If you see a meteor try to trace it backwards. If you end up in the constellation Perseus, there’s a good chance you’ve seen a Perseid. If finding constellations isn’t your forte, then note that Perseids are some of the fastest meteors you’ll see!
Pro tip: Remember to let your eyes become adjusted to the dark (it takes about 30 minutes) – you’ll see more meteors that way. Try to stay off of your phone too, as looking at devices with bright screens will negatively affect your night vision and hence reduce the number of meteors you see!
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.
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.
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.”
There was a very bright green fireball seen by hundreds of eyewitnesses surrounding Lake Michigan early this morning at 1:25:13 AM Central Time (February 6, 2017). The reports from these individuals and the video information from dash cameras and other cameras in the region indicate that the meteor originated 62 miles above West Bend, Wisconsin and moved northeast at about 38,000 miles per hour. It disrupted about 21 miles above Lake Michigan, approximately 9 miles east of the town of Newton. The explosive force of this disruption was recorded on an infrasound station in Manitoba, some 600 miles away – these data put the lower limit energy of the event at about 10 tons of TNT, which means we are dealing with a meteoroid – orbit indicates an asteroidal fragment – weighing at least 600 pounds and 2 feet in diameter. Doppler weather radar picked up fragments (meteorites) falling into Lake Michigan near the end point of the trajectory.
Ground track and Doppler radar signature (done by Marc Fries at NASA Johnson Space Center); an animation of the orbit and approach of the meteoroid is being prepared and should be available soon. We will continue to look at data as it comes in and revise the calculations if necessary.
We have received numerous reports concerning a bright fireball that occurred over Georgia at 5:33:55 PM CST (6:33:55 PM EST). All 6 NASA all sky meteor cameras in the Southeast picked up the meteor at an altitude of 50 miles above the town of Georgia (SE of Atlanta). From its brightness, it is estimated that this piece of an asteroid weighed at least 150 pounds and was over 16 inches in diameter. It entered the atmosphere at a steep angle and moved almost due south at a speed of 29,000 miles per hour. The NASA cameras tracked it to an altitude of 17 miles above the town of Locust Grove, where it had slowed to a speed of 9000 miles per hour, at which point the meteor ceased producing light by burning up. It is possible that fragments of this object survived to reach the ground as meteorites.
A more detailed analysis will be performed tomorrow and further details will follow if this analysis still indicates the possibility of a meteorite fall.
Composite image showing bright event located near Rosman, North Carolina.
There was a bright event seen across several Southeast states last night at 12:29:30 AM CDT (1:29:30 EDT). Based on the data we currently have, this object was not a meteor or fireball. Tracked by 5 NASA cameras in the SE, it is moving at roughly 14,500 miles per hour, which is too slow to be a meteor. As you can see in the video, it has also broken into multiple pieces, which, combined with the slow speed, indicates a possible reentry of space debris. There are over 120 eyewitness accounts on the American Meteor Society website (www.amsmeteors.org)
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.
At approximately midnight local time on the night of September 6 (September 7, 6 UTC), a loud explosion was heard in an area near Managua, Nicaragua. A crater some 39 feet in diameter was found near 86.2 degrees west longitude, 12.2 degrees north latitude, in good agreement with the reports of explosive sounds. It has been suggested that a meteorite may have caused this crater; however, the lack of fireball reports from the surrounding populated area seems to suggest some other cause. The skies were partially clear, and an object capable of producing a crater this large would have also generated a very bright fireball (brighter than the Full Moon) that should have been seen over a wide area. Some have drawn analogies to the September 2007 Carancas meteorite fall in Peru; however, there were fireball reports associated with this event, even though it occurred in the daytime near noon.
While a meteoritic origin for this crater cannot be ruled out with absolute certainty, the information available at this time suggests that some other cause is responsible for its creation.
We have completed our analyses and here’s what we know:
At 10:19 PM Central Daylight Time on August 2 (Saturday night), NASA meteor cameras detected a very bright fireball at an altitude of 57 miles above Hoodoo Road just east of the town of Beechgrove, TN. The meteoroid, which was about 15 inches in diameter and weighed close to 100 lbs, travelled just over 100 miles to the south south east at 47,000 miles per hour, breaking apart in a brilliant flash of light above the Alabama town of Henagar. The cameras continued to track a large fragment until it disappeared 18 miles above Gaylesville, located near Lake Weiss close to the Georgia state line. At last sight, the fragment was still traveling at 11,000 miles per hour. Based on the meteor’s speed, final altitude, and weak doppler radar signatures, it is believed that this fireball produced small meteorites on the ground somewhere between Borden Springs, AL and Lake Weiss.
The meteoroid’s orbit has its farthest point between the orbits of Mars and Jupiter, and is inclined to that of the Earth (which explains its southerly direction).
The NASA Meteoroid Environment Office would like to hear from those in the area around Alabama’s Lake Weiss who may have heard sonic booms or like sounds around 10:20 PM Saturday night. Please contact Dr. Bill Cooke at firstname.lastname@example.org if you have reports of such.