The eta Aquariid meteor shower is active throughout April and May, peaking in the pre-dawn hours of May 5. This year could be particularly impressive as an outburst year with 120-160 meteors per hour expected.
“A meteor shower is like a normal rain shower, with 50-60 meteors per hour,” said Bill Cooke, lead of NASA’s Meteoroid Environments Office at the agency’s Marshall Space Flight Center in Huntsville, Alabama. “An outburst is like a thunderstorm, with greater than normal meteor activity expected. A meteor storm is like a tornado, where meteor rates are over one thousand per hour.”
Despite the full moon lighting up the sky and washing out the faint meteors, this year’s eta Aquariid meteor shower is not one to miss. In terms of producing fireballs, NASA camera data places it #6 among meteor showers. These bright fireballs are caused by Earth running into a dense stream of debris from Comet Halley, a lot of which was ejected more than 3,000 years ago. Moving at 148,000 mph, some of these fireballs leave glowing “trains” in their wake that last for several seconds to minutes.
How to View
The eta Aquariid meteor shower is viewable in both the Northern and Southern hemispheres, with higher rates of visibility to observers in the Southern Hemisphere. This is due to the radiant’s location in the constellation of Aquarius. Meteors will be observable after midnight, but the peak times are 3-4 a.m. until dawn.
Regardless of your geographic location, you’ll want to find an area well away from city lights for best viewing. Give yourself about 30 minutes in the dark for your eyes to adapt – this means not looking at your phone. Look AWAY from the moon and take in as much sky as possible.
The next major meteor showers will be the Perseids in August, and the sister show to the eta Aquariids, the Orionids in October.
But there’s plenty more skygazing to do this month. Check out What’s Up in May from NASA Jet Propulsion Laboratory.
This year’s Lyrid meteor shower will peak in the predawn hours of April 23. On average, the shower can produce up to 15 meteors per hour under ideal viewing conditions. The Lyrids occur every year in mid-April, when Earth crosses the trail of debris left by the Comet C/1861 G1 Thatcher. These bits of comet burn up when they hit Earth’s atmosphere and produce this shower of shooting stars. The shower gets its name from the constellation Lyra, the point in the sky where the meteors appear to originate. Unlike the Perseids or Geminids, the Lyrids are not known for bright fireballs. What makes them special is their unpredictability.
The first record of the Lyrid meteor shower dates back 2,700 years, making it one of the oldest in history. Researchers looking though old records have found descriptions of major Lyrid outbursts. For example, a notation made by the French bishop Gregory of Tours in April of 582 A.D. states, “At Soissons, we see the sky on fire.” There was also a Lyrid outburst visible over the United States in 1803. An article in the Virginia Gazette and General Advertiser describes the shower: “From one until three, those starry meteors seemed to fall from every point in the heavens, in such numbers as to resemble a shower of sky rockets.” The last Lyrid outburst was in 1982, when 75 meteors per hour were recorded by observers in Florida.
The common theme here is that Lyrid outbursts are surprises. Unlike some other showers, meteor researchers aren’t able to predict Lyrid outbursts as well. That’s why it is important to make observations each year so that models of its activity can be improved.
How can you best observe the Lyrids? After 10:30 p.m. local time on the night of April 22, find a dark place away from city lights with open sky free of clouds and look straight up. It will take about 30 minutes for your eyes to get acclimated to the dark. Don’t look at your cell phone – the bright light from its screen will interrupt your night vision. You will begin to see Lyrids, and as the night progresses the meteors will appear more often, reaching 10 to 15 per hour in the pre-dawn hours of the 23rd. You can see Lyrids on the night before and after the peak, but the rates will be lower, maybe five per hour or so.
The cosmos’ annual gift to sky watchers, the Geminids Meteor shower, will peak on Dec. 13-14 this year.
During peak activity and perfect weather conditions, which are rare, the Geminids produce approximately 100-150 meteors per hour for viewing. However, this year a waning gibbous moon will make it harder to view most of the shower, resulting in only 30-40 visible meteors per hour at the peak in the Northern Hemisphere, depending on sky conditions. But the Geminids are so bright that this should still be a good show.
Bill Cooke, lead of NASA’s Meteoroid Environments Office at Marshall Space Flight Center in Huntsville, Alabama, suggests sitting in the shade of a house or tree while also maintaining a view of the open sky to alleviate moonlight interference.
The meteor shower is coined the Geminids because the meteors appear to radiate from the constellation Gemini. According to Cooke, meteors close to the radiant have very short trails and are easily missed, so observers should avoid looking at that constellation. However, tracing a meteor backwards to the constellation Gemini can determine if you caught a Geminid (other weaker showers occur at the same time).
Gemini does not appear very high above the horizon in the Southern Hemisphere, resulting in viewers only seeing approximately 25% of the rates seen in the Northern Hemisphere, which is between 7-10 meteors per hour. Sky watchers from the Southern Hemisphere are encouraged to find areas with minimal light pollution and look to the northern sky to improve their viewing opportunities.
The Geminids start around 9 or 10 p.m. CST on Dec. 13, making it a great viewing opportunity for any viewers who cannot be awake during later hours of the night. The shower will peak at 6 a.m. CST on Dec. 14, but the best rates will be seen earlier around 2 a.m. local time. You can still view Geminids just before or after this date, but the last opportunity is on Dec. 17 – when a dedicated observer could possibly spot one or two on that night.
For prime viewing, find an area away from city and streetlights, bundle up for winter weather conditions, bring a blanket or sleeping bag for extra comfort, lie flat on your back with your feet facing south, and look up. Practice patience because it will take approximately 30 minutes for your eyes to fully adjust and see the meteors. Refrain from looking at your cell phone or other bright objects to keep your eyes adjusted.
The show will last for most of the night, so you have multiple opportunities to spot the brilliant streaks of light across our sky.
So where does this magnificent shower come from? Meteors are fragments and particles that burn up as they enter Earth’s atmosphere at high speed, and they usually originate from comets.
The Geminid shower originates from the debris of 3200 Phaethon an asteroid first discovered on Oct. 11, 1983, using the Infrared Astronomical Satellite. Phaethon orbits the Sun every 1.4 years, and every year Earth passes through its trail of debris, resulting in the Geminids Shower.
Phaethon is the first asteroid to be associated with a meteor shower, but astronomers debate its exact classification and origins. Phaethon lacks an icy shell (the staple characteristic of a comet), but some consider it a “dead comet” – suggesting it once had an icy shell that melted away. Other astronomers call it a “rock comet” because Phaethon passes very close to the Sun during its orbit, which theoretically results in heating and cracking that creates debris and dust. The bottom line is Phaethon’s exact origins are still a mystery, but we do know it’s the Geminids parent body.
Geminids travel 78,000 miles per hour, over 40 times faster than a speeding bullet, but it is highly unlikely that meteors will reach the ground – most Geminids burn up at altitudes between 45 to 55 miles.
In addition to sky watching opportunities, meteor videos recorded by the NASA All Sky Fireball Network are available each morning to identify Geminids in these videos – just look for events labeled “GEM.”
And, if you want to know what else is in the sky for December, check out the video below from Jet Propulsion Laboratory’s monthly “What’s Up” video series:
For Comet Vocabulary, please read to the end of the post.
For most, early July is when most people living in the United States look to the skies to watch dazzling firework shows. However, this month there is a different kind of show happening in the sky.
Comet Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) was only discovered a few months ago on March 27 by NASA’s NEOWISE telescope and has quickly become a popular solar system visitor. Its popularity is warranted, however, as it is the brightest comet since Comet Hale-Bopp that passed by Earth 23 years ago in 1997.
Comet nuclei are cosmic snowballs of frozen gases, rock and dust that orbit the sun. They can range in size from a few miles to tens of miles wide, and the nucleus of NEOWISE measures about 3 miles across. When these comets approach the sun, their frozen bodies start to sublimate, and they spew dust and gasses in a tail that can span millions of miles.
Comet NEOWISE made its harrowing close approach to the sun, known as its perihelion, on July 3, and it is now zooming past the Earth on its way back out of the solar system. NEOWISE will make its closest approach (64 million miles) to Earth on July 22, but the best viewing window is happening right now until July 19.
NEOWISE can be seen with the naked eye, but for an even better viewing experience, binoculars or even a telescope is recommended. As for which to choose, binoculars are your current best option. “Definitely use binoculars for now – the tail of NEOWISE is at least 7 degrees long, which is much bigger than the field of view of most telescopes,” said Bill Cooke, lead of NASA’s Meteoroid Environment Office at Marshall Space Flight Center. “Binoculars will allow you to see the whole thing, whereas a telescope only shows a tiny part.”
To see NEOWISE, start looking in the northwestern sky about an hour after sunset. The comet will be below the stars that make up the bowl of the Big Dipper and shining nearly as brightly at a magnitude 3. If you are an early riser, you can still see NEOWISE about an hour before sunrise in the northeastern horizon until the end of the week.
You need a clear view of the horizon to see this comet. Beaches, fields, and areas with higher elevations are all great observation spots. In areas with more light pollution, binoculars may be necessary for viewing. This is definitely a once-in-a-lifetime event, as NEOWISE won’t be visiting again for 6,800 years!
By: Bill Cooke
Lead, NASA Meteoroid Environment Office
The media is currently broadcasting the prediction of an outburst of the alpha Monocerotid meteor shower on the night of November 21. The researchers making the prediction, Dr. Peter Jenniskens and Esko Lyytinen, have made calculations that indicate that there may be zenithal hourly rates as high as 400 to 1000 meteors per hour around 11:50 PM Eastern Standard Time (10:50 PM Central and 9:50 PM Mountain; you will note that I am not giving a Pacific time – more on that later). These are impressive numbers, generating lots of buzz in the media. I love meteor outbursts and storms, so I was initially quite excited – I mean, what’s there not to like about an impromptu display involving lots of meteors from a yet-to-be discovered comet?
But as the media inquiries increased, I began to wonder if all the attention is justified. Being a meteor shower forecaster, I am all too aware of the fact that such predictions (including mine), while pretty accurate on the timing, often estimate a shower intensity higher (factors of a few) than what actually takes place. So I decided to take a more detailed look, starting with some dumpster diving for old papers about this shower and making a few calculations of my own. That’s when the skepticism kicked in – I now think there is a pretty good chance there may be no outburst at all. And even if there is, it won’t be as impressive as many think. Allow me to share…
In Dr. Jenniskens and Lyytinen’s work, the Earth is forced to pass through the center of alpha Monocerotid meteor stream (AMOs for short) during the shower’s 1925 and 1935 outbursts. We have no idea if this actually happened, but it is a reasonable assumption if these outbursts were more intense than the last one in 1995. Based on this, they conclude that the AMOs are produced by a long period comet that takes about 500 years to orbit the Sun. IF this is right, then we should pass very close to the center of the meteor stream this year, missing it by a scant 15,000 miles. That’s just a tad closer than we got back in 1995, when the observed zenithal hourly rate was about 400 per hour. And it’s why the forecast rate is so high – closer means the same intensity or better.
However, the intensity of the outburst is very dependent on the size of the parent comet’s orbit. If it is much smaller, or larger, the distance from the stream center will be bigger, and there will not be any sky show, just the normal AMOs, puttering along with their normal rate of 3 or so meteors per hour. And since we have not yet discovered this mysterious parent comet, who knows how close the estimate of the orbit is to the actual? A good reason to step outside Thursday night, because the cool thing is that if an outburst does occur, we will have a pretty good idea of the orbit of this comet – not from observing the comet with telescopes, but by counting its debris as they burn up in our atmosphere.
The old papers I dug up also proved enlightening. I could find no meteor rate numbers for the 1925 outburst – just that it was short, with a fair number of meteors. The 1935 AMO outburst was observed in 2 places – a meteor observer in Begumpet, India and the commanding officer of a U.S. ship in the Philippines each reported seeing a total of just over 100 meteors in a 40 minute span of time. That’s nice, but it certainly is nowhere close to the spectacular rates produced by the Leonid and Draconid meteor storms of the 1900’s. A moderate outburst, yes, but not a meteor storm. Even fewer were seen in 1985, when one observer reported 36 meteors seen over 16 minutes of time. It is true that the calculated rates were in the hundreds per hour, but what matters to the average person is the total number of meteors they will see. Zenithal hourly rates give the theoretical rates for a perfect observer under perfect skies with the shower radiant straight overhead (something that never happens in reality), and while they may be a good way to scientifically measure meteor shower activity, they are poor indicators of what will actually be seen. The observer reports, however, do tell us what we might expect.
And then we come to 1995, the best-observed AMO outburst. Quite a few observers in Western Europe saw about 100 meteors over an hour’s time, consistent with the observations of the previous AMO outbursts. These data do not indicate that we were closer to the AMO stream center in 1925 and 1935, as Jenniskens and Lyytinen suggest; in fact, it appears that AMO outbursts are fairly constant with regard to numbers, with about 100 meteors seen over the less-than-an-hour duration of the outburst. At face value, this would mean no outburst. However, the numbers seeming to be not strongly dependent on distance is possibly good news; even if the researchers’ distance assumptions are wrong, we still may have a chance of a respectable, albeit short, outburst, provided Earth gets “close enough” to the stream center.
At the beginning of this post, I gave times for the predicted peak in the Eastern, Central, and Mountain time zones, but left out Pacific. That’s because the AMO radiant – the point in the constellation of Monocerotis from which the meteors appear to originate – is below the horizon at the peak time for locations west of Denver. That means people on the Pacific Coast will not see this outburst, even if their skies are clear. So if you live there and want to experience the shower, you need to go quite a bit east. If you do, please don’t blame me if the outburst is a no show; as I said, I am a bit skeptical. For the eastern United States, the radiant is not very high in the sky at the forecast peak time (about 23° in Orlando), which is unfortunate since the observed number of meteors is tied to the radiant altitude. The higher the radiant, the more meteors people see. So my computer savvy colleagues have generated this map, which shows the total numbers of meteors you can expect to see if the outburst is similar to that of 1995. Blue is good, red is worse, white means no meteors at all. The decrease in total expected meteors is pretty obvious as you move west
And of course, there is the weather. Remember, you need clear, dark skies to see meteors, and it looks like Mother Nature is going to be mean, with clouds forecast over much of the part of the U.S. that has a chance of observing the outburst. So, if you are gifted with good seeing, give yourself about 45 minutes to adjust to the dark – go out about 10:35 PM Eastern, 9:35 PM Central, or 8:35 PM Mountain. Lie flat on your back, look straight up, and enjoy looking at the night sky (maybe listen to some appropriate tunes, but don’t look at your cell phone, as the bright screen will ruin your night vision). If Jenniskens and Lyytinen are right, you might see some pieces of a comet that awaits discovery, burning up in the atmosphere 60 miles above your head.
That’s worth a couple of hours, I think. Even if there is no outburst, it doesn’t hurt to get out under the stars for a bit.
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.