April has already been an active month for celestial events and it is about to get even better with the Lyrid meteor shower beginning April 19. Just in time for the 50th anniversary of Earth Day, the Lyrids will peak on April 22 during the predawn hours.
A new Moon this year will make way for good viewing of the Lyrids, leaving the sky dark. While rates of Lyrids per hour can be low, they are also known to produce bright fireballs, and this year we are expecting rates of up to 15 meteors per hour.
The Lyrids are pieces of space debris that originate from the comet C/1861 G1 Thatcher. They are one of the oldest known meteor showers, having been observed for over 2,700 years. Their radiant, or point in the sky from which they appear and where they get their name, is in the constellation Lyra. The Lyrids appear to come from the vicinity of one of the brightest stars in the night sky – Vega. Vega is one of the easiest stars to spot, even in light-polluted areas.
“This will actually be a good year for the Lyrids and it is exciting the peak is on Earth Day and in the middle of International Dark Sky Week,” said Bill Cooke, lead of NASA’s Meteoroid Environment Office at NASA’s Marshall Space Flight Center. “While the Lyrids aren’t as prolific as other meteor showers like the Perseids or Geminids, they usually do produce some bright fireballs, and since the Moon will be nearly invisible April 22, rates should be about as good as it gets for this shower.”
Due to the ongoing COVID-19 pandemic, NASA plans to observe Earth Day virtually this year, and will highlight the agency’s many contributions to sustaining and improving our home planet with a week of online events, stories and resources. With the Lyrids peaking on April 22, the day is shaping up to be full of observations and science, including the “NASA Science Live” broadcast airing at 3 p.m. EDT. The special Earth Day episode will explore important discoveries about our home planet, advances in green technology and aircraft.
Not only do the Lyrids coincide with Earth Day this year, the shower also falls (pun intended!) during International Dark Sky Week which begins April 19 and goes to April 26. This international observance focuses on preserving and protecting our night sky and the wonders that comes with it.
As spring blooms in the Northern Hemisphere, here’s what’s happening in the night sky!
Venus On April 3, Venus will pass near a star cluster known as the Pleiades. Also known as the Seven Sisters or M45, the Pleiades lies about 400 light years away from Earth, toward the constellation of the Bull — or Taurus.
Last year as Venus passed close to the Pleiades on June 9, the planet was five degrees south of the star cluster — 20 times farther away than it will be this year. Next year, Venus will be close to the star cluster once more on April 9 — this time at four degrees south of the Seven Sisters. This 2021 passing will be 16 times farther away than the 2020 event.
This year, viewers will have the rare chance at a brilliant view of Venus on April 3. With the naked eye, you will see something similar to the illustration below. However, the best view will be achieved through a pair of binoculars. Don’t miss your shot — Venus won’t make another appearance this close to the Pleiades until 2028!
Supermoon We will have a Full Moon on April 7 at 9:35 p.m. CDT, at which time the Moon will be near to its perigee — or the point in its orbit that it is closest to Earth. This proximity will provide the largest appearance of the Moon for the whole year, commonly called a supermoon.
With the Artemis Program, NASA will land the first woman and next man on the Moon by 2024, using innovative technologies to explore more of the lunar surface than ever before. We will collaborate with our commercial and international partners and establish sustainable exploration by 2028. Until that day arrives, the supermoon will put us all a bit closer (physically) to our goal!
Comet C/2019 Y4 ATLAS NASA astronomer Tiffany Clements recently captured the below image of Comet C/2019 Y4 ATLAS using a wide field telescope in New Mexico. Discovered at the end of December 2019 by an automated sky survey searching for Earth-approaching asteroids, this comet could brighten enough to be visible by late May or early June. However, comets are notoriously unpredictable, so stay tuned!
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.
The sky will put on a show Nov. 11 when Mercury journeys across the Sun. The event, known as a transit, occurs when Mercury passes directly between Earth and the Sun. From our perspective on Earth, Mercury will look like a tiny black dot gliding across the Sun’s face. This only happens about 13 times a century, so it’s a rare event that skywatchers won’t want to miss! Mercury’s last transit was in 2016. The next won’t happen again until 2032!
“Viewing transits and eclipses provide opportunities to engage the public, to encourage one and all to experience the wonders of the universe and to appreciate how precisely science and mathematics can predict celestial events,” said Mitzi Adams, a solar scientist in the Heliophysics and Planetary Science Branch at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “Of course, safely viewing the Sun is one of my favorite things to do.”
This year’s transit will be widely visible from most of Earth, including the Americas, the Atlantic and Pacific Oceans, New Zealand, Europe, Africa, and western Asia. It starts at about 6:35 a.m. CST, but viewers in some areas, such as the West Coast, will have to wait until the Sun rises at their location to see the transit already in progress. Thankfully, this transit will last almost six hours, so there will be plenty of time to catch the show. At about 9:20 a.m. CST, Mercury’s center will be as close as it is going to get to the Sun’s.
Mercury’s tiny disk, jet black and perfectly round, covers a tiny fraction of the Sun’s blinding surface — only 1/283 of the Sun’s apparent diameter. So you’ll need the magnification of a telescope (minimum of 50x) with a solar filter to view the transit. Never look at the Sun directly or through a telescope without proper protection. It can lead to serious and permanent vision damage. Always use a safe Sun filter to protect your eyes!
Scientists have been using transits for hundreds of years to study the way planets and stars move in space. Edmund Halley used a transit of Venus in 1761 and 1769 to determine the absolute distance to the Sun. Another use of transits is the dimming of Sun or star light as a planet crosses in front of it. This technique is one way planets circling other stars can be found. Scientists can measure brightness dips from these other stars (or from the Sun) to calculate sizes of planets, how far away the planets are from their stars, and even get hints of what they’re made of.
As we head into the darker half of the year here in Earth’s Northern Hemisphere, astronomers at NASA’s Meteoroid Environment Office are sharing eerie images from their meteor cameras. The specialized cameras are part of a network set up by the meteor team to observe and study fireballs — meteors brighter that the planet Venus. Here’s a look at the some of the birds, bugs and stranger things that have crept from the shadows into their view.
Images and video of fireballs from the cameras are available for anyone to download from NASA’s All-Sky Fireball Network. For a complete album of our favorite eerie images from the cameras, visit Marshall’s Flickr gallery.
Heads up, skywatchers! Did you know there’s a night set aside each year to celebrate and observe our Moon? International Observe the Moon Night has been held annually since 2010. This year it’s Saturday, Oct. 5.
This year also offers an opportunity to celebrate lunar exploration at a time when we are preparing to land American astronauts, including the first woman and the next man, on the Moon by 2024. Through the NASA’s Artemis lunar exploration program, we will use innovative new technologies and systems to explore more of the Moon than ever before, and use that knowledge to take the next giant leap, sending astronauts to Mars.
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.”