See the feisty fireballs of November’s Taurid meteor shower

At least four fragments are seen in this closeup of Comet Hergenrother’s bright nucleus taken early on Nov. 2, 2012 by the Gemini North telescope in Hawaii. The comet is currently 266 million miles from Earth. Credit: NASA/JPL-Caltech/NOAO/Gemini

November’s brightest comet – 168P/Hergenrother – continues to splinter. On Oct. 25, the Italian amateur astronomer team of Ernesto Guido, Nick Howes and Giovanni.Sostero  were the first to photograph a fragment shed from the comet’s bright head or nucleus using the 79-inch Faulkes Telescope.

Deeper observations with the National Optical Astronomy Observatory’s huge 323-inch Gemini North telescope on Mauna Kea in Hawaii now show at least four chunks broken loose from the nucleus:

“We have resolved that the nucleus of the comet has separated into at least four distinct pieces resulting in a large increase in dust material in its coma,” said Rachel Stevenson, a post-doctoral fellow working at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

The more dust, the brighter the comet will appear since there’s more material to reflect sunlight. Hergenrother has faded some recently but still shines at about 10.5 magnitude (my estimate) and makes a fine target for amateur telescopes. Look for it high in the southeastern sky during early evening hours. Click HERE for a finder chart.

The Northern and Southern Taurid meteor showers are active in early November. Taurids are sparse but often bright and appear to radiate from the direction of the Pleiades star cluster in Taurus. Map shows the sky facing east around 11 ‘o clock local time. Created with Stellarium

Meteors come from comets. They’re the dust that gets boiled off the comet’s nucleus and pushed down the tail by sunlight. As a comet travels around the sun, it leaves a trail of gritty crumbs in its wake. Earth crosses some of these trails at particular times of year giving rise to familiar meteor showers like the August Perseids and December Geminids.  Dust slams into our atmosphere at thousands of miles an hour and quickly vaporizes, creating a glowing tube of light or meteor.

The Taurid shower contains larger comet crumbs than other showers. They travel relatively slowly – 65,000 mph – compared to the Leonids or Perseids and show as bright, slow fireballs. Credit: NASA

There’s more going on besides the election next week. Nov. 5-13 marks the peak of the Northern and Southern Taurid meteor showers. Showers usually hit maximum over a one or two day period, but the Taurids have a broad plateau lasting weeks. At peak, you might see around 7 meteors per hour.

You’re welcome to pull up a chair and face east or south for an hour, but you may be disappointed. Given their broad distribution, Taurid meteors are more likely something you’ll see while you’re outside at night doing something else.

While sparse, the dual showers are famed for their slow fireballs. If you see a brilliant, orange-colored meteor slowly arcing across the sky and can trace its path back toward the Pleiades, chances are you’ve caught a Taurid. I’ve seen a few over the years and remember them as not only bright but breaking into pieces as they burned up overhead.

Comet Encke and the trail of dust and debris it leaves behind in its orbit photographed by the Spitzer Space Telescope. Credit: NASA

The Southern Taurids peak on the 5th; the northern version on Nov.12-13th. Both showers are connected to Encke’s Comet or possibly a larger comet that broke into fragments in a manner similar to Comet Hergenrother. One of the fragments became Encke’s Comet while other chunks of debris may have evolved into the dual showers.

Meteor showers normally appear to radiate from one spot in the sky. The double radiant for the Taurids tells us this is an ancient meteor stream that has diverged and spread out over time from the accumulated gravitational tugs of the sun and planets. This year we’re expected to cross a thicker-than-usual stream of comet dust, so expect a slightly better chance of seeing your first Taurid meteor. The best time to watch is later at night after 11 o’clock, when Taurus and the Pleiades are high are in the eastern sky. For more details on the Taurids click HERE.

California fireball fragment hits pastor’s home in Novato

Lisa Webber, meteorite finder.

Call it a message from heaven, but the first meteorite reported from the Oct. 17 fireball that lit up the sky over the San Francisco Bay area struck the roof of the Rev. Kent and Lisa Webber’s home in Novato’s Pleasant Valley neighborhood. Kent is pastor of Novato’s Presbyterian Church. Lisa works as the head nurse at the Department of Dermatology of the University of California, San Francisco Medical Center.

While relaxing at home last Wednesday night watching TV, she heard a boom and then something rattling around on the roof. She walked outside for a look, but didn’t find anything amiss … at first.

The dark-crusted rock found by Lisa Webber in Novato, Calif. weighs 63 grams or 2.2 ounces. The meteorite “appears to be a breccia with light and dark parts” according to Dr. Jenniskens. Credit: Peter Jenniskens

Later last week, Lisa’s curiosity was piqued by Dave Perlman’s article in the San Francisco Chronicle on Saturday, describing the NASA/CAMS meteor trajectory predicted impact area centered on Novato. Lisa decided to make a more thorough search and turned up an unusual rock near her side gate. A neighbor’s son suggested she test it with a magnet. She did and it stuck! Not a guarantee of a meteorite but a very good sign all the same.

Preliminary trajectory calculated by Peter Jenniskens from Sunnyvale and San Mateo College Observatory CAMS video data. The possible fall zone is shown in white and contained in the circle. Credit: Peter Jenniskens

Webber contacted Dr. Peter Jenniskens, who runs NASA’s Cameras for AllSky Meteor Surveillance or CAMS, an automated video surveillance program of the night sky in search of meteors.

Two CAMS cameras in different locations in the Bay area triangulated the fireball’s path. Based on the picture data, Jenniskens predicted a potential landing zone in funnel-shaped zone east of San Rafael, over Novato and toward Sonoma.

He and the Webbers’ neighbor Luis Rivera inspected the roof and found an impact pit or divot in a shingle that matched up nicely with the meteorite’s size. Usually the smallest meteorites drop first with the larger ones moving farther ahead before they fall too. Because the fireball traveled from SW to NE, Jenniskens thinks it likely larger fragments dropped nearer Sonoma northeast of Novato.

Luis Rivera points to the impact dent on the Webbers’ roof. Credit: Peter Jenniskens

“The significance of this find”, says Jenniskens, “is that we can now hope to use our fireball trajectory to trace this type of meteorite back to its origins in the asteroid belt,” said Jenniskens. The find also helps start the process of defining the orientation and location of the meteorite drop-zone or strewnfield.

Rain’s expected in the area today – something meteorites don’t like. Rain makes for rust and breakdown by erosion. Jenniskens hopes more of the space bounty comes to light before a soaking. If you’re in the area and think you’ve found a fragment of cosmic rock, contact him at this e-mail:

By the way, you’ll still see stories claiming this meteorite came from the weekend Orionid meteor shower. It didn’t. The fireball blew in from a completely different direction opposite Orion.

I want to thank Dr. Jenniskens for pictures and information from the CAMS site used for this article.

** UPDATE Oct. 23, 2012 — The rock is not a meteorite after all! As per Peter Jenniskens:

“We examined the rock with a petrographic microscope yesterday, says Jenniskens, and quickly concluded it was not a meteorite. I sincerely thought it was, based on what appeared to me was remnant fusion crust. On closer inspection, that crust was a product of weathering of a natural rock, not from the heat of entry.” He searched the ground again with Lisa Webber but failed to a meteorite. So how did that hole get in that roof shingle?

NASA video of California fireball helps narrow fall zone

San Mateo College student Paola-Castilla photographed the fireball on a cell phone while stuck in traffic. Credit: Paola-Castillo

Either meteorites haven’t been found yet or nobody’s talkin’. But videos and eyewitness reports have allowed Peter Jenniskens, principal investigator at SETI Institute, to paint a more detailed picture of the fireball that blazed over the San Francisco Bay area Wednesday evening.

Jenniskens examined the images recorded by two CAMS (Cameras for AllSky Meteor Surveillance) cameras, one near Sunnyvale and another at San Mateo College. Data from two widely-spaced places gives researchers the ability to triangulate distances and altitudes of a meteor’s flight.

The fireball was so bright in NASA’s sensitive camera, it blew out the image, creating some trippy effects.

The cameras tracked the car-sized space boulder from when it started to glow at 53 miles overhead down to 24 miles, when it exploded to pieces. Top speed was 31,300 mph. Jenniskens believes there’s a “good chance a relatively large fraction of this rock survived.”

Peter Jenniskens

Before meeting its earthly fate, the meteoroid circled the sun with a perihelion (closest point to the sun) of 91.8 million miles in nearly the same plane as Earth’s orbit. Practically a next door neighbor. Jenniskens began his search the hills north of the Bay area Friday for meteorite fragments. Let’s hope he finds a few!

If you were (are) in the area and wish to share videos and photographs and report possible meteorite finds, please email:

Oct. 17 California fireball may have dropped meteorites

Last night’s fireball over Belmont, California. The meteor first appears in the constellation Sagittarius and flamed across Ophiuchus and Hercules. The Summer Triangle of Vega, Deneb and Altair is at center and tipped sideways with north to the right. Credit: Wes Jones

Although the Orionid meteor shower’s up at bat this weekend, meteors fall anytime. Those that drop from a random spot in the sky and aren’t connected to a specific comet, as the Orionids are with Halley’s Comet, are called sporadic meteors. On any given night you might see 5-10 sporadic meteors per hour.

Yesterday evening October 17 at 7:42 p.m. local time, a brilliant sporadic meteor created a sensation over the San Francisco Bay-San Jose region where it briefly lit up the night sky like a thousand sparklers. The fireball broke into pieces as it fell, rumbled like thunder and left a glowing train (luminous trail) in its wake. To hear some of the comments posted on the American Meteor Society’s Fireball Report website makes you wish you were there:

“Awesome wild glowing train that turned to smoke.” – Karen

“It must have been really big and/or really bright because it created shadows on the street and the delay between the first shadows appearing and the delayed boom was maybe more than a minute. It was so bright it created shadows on the road from the overhead powerlines.” – Alicia

“The sound was stretched out and there were several pulses, like distant thunder, but louder. After it passed overhead it broke into a number of pieces which continued in the same direction at first and then some diverged near end.” – Frank

“The fireball was clearly breaking up as it flew across the sky. it made the tail appear like a firework sparkler with blue and red and yellow sparks flying off.” – Amanda Titterington

Security cameras at California’s Lick Observatory recorded the fireball. The round, silhouetted structure at left is the telescope dome and the lights in the background are from San Jose.

While some news articles are connecting the fireball to the Orionid meteor shower, it’s completely unrelated. How do we know? The photo above clearly shows it originating in the Sagittarius area located in the opposite part of the sky from Orion. Orionids fly out of Orion which at the time had yet to rise. Because of the meteor’s slow speed, its breakup into fragments and reports of thundery booms that shook residents’ homes after it disappeared from view, there’s a fair chance it may have dropped meteorites. Meteors rumble, thunder and boom when they enter the lower atmosphere traveling faster than the speed of sound.

Meteorite hunters will be checking Doppler weather radar recordings made in the fall zone to see if they can pinpoint a possible search location. Jonathan Braidman of Oakland’s Chabot Space and Science Center, believes that fireball fragments may have fallen in hilly terrain north of Martinez, Cal. For the latest news and reports, please click over to Dirk Ross’s excellent Latest Worldwide Meteorite / Meteorite News site.

X your calendar for Sunday’s Orionid meteor shower

This map shows the sky facing south around 5 a.m. Sunday morning October 21, 2012. The Orionids will appear to radiate from the “shoulder” of Orion the Hunter not far from the brilliant planet Jupiter. Created with Stellarium

Don’t stay up too late this coming Saturday night. You’ll need your sleep before rising for the annual Orionid meteor shower which peaks early Sunday morning October 21. As many as 25 meteors per hour will be visible from a dark sky. This shower guarantees at least a minor show compared to the more fickle Draconids earlier this month. As long as the moon’s out of the sky and you live along the suburban fringe of a city or out in the country, you’ll see meteors. This weekend the moon sets long before the shower peaks, tempting even the hard-bitten I-hate-getting-up-before-sunrise-crowd to step outside for a look.

Halley’s Comet swings near Earth every 76 years. This comic, created by an unknown author, captures the poignancy of the comet’s multiple appearances. Dust left by the comet arrives each year as the Orionid meteor shower.

Each streak of light you see signals the incineration of a flake of Halley’s Comet, the parent comet of the Orionids. Every year in late October, Earth cuts across Halley’s orbit and bits of dust shed by the comet from previous passes near the sun burn up as they strike the upper atmosphere at speeds of 148,000 mph. Few showers offer up faster meteors.  I can attest to the Orionids’ high speed. Every one I’ve ever seen sure appeared to be in a big hurry; most tear across the sky in second or less.

You can start watching for Orionids a couple hours before morning twilight begins or from 4 a.m. Sunday onward. Face south and get cozy under a big blanket or in a sleeping bag to stay warm. The shower lasts a few days, so if the weather’s looks bad, try the mornings before and after.

Path of the International Space Station shown on one of the new sky charts on Heavens Above. This map shows the track for Duluth, Minn. this evening Oct. 16 starting around 7:18 p.m. Credit: Heavens Above / Chris Peat

For evening sky watchers, the International Space Station continues its series of passes during convenient viewing hours this week. Watch for a brilliant yellow “star” traveling from west to east across the northern sky. The times listed below are for the Duluth, Minn. region. To get specific times and maps for your town, log on to Heavens Above. Chris Peat at Heavens Above just unveiled brand new sky maps that will make finding the station and anticipating its track even easier. A single click on any part of a new chart lets you zoom in. Click again to zoom out. I’ve included an example above.

You can also go to Spaceweather’s Satellite Flybys link and type in your zip code for flyover times (no maps).

Tuesday Oct. 16 starting at 7:19 p.m. High and bright pass in the northern sky
Wednesday Oct. 17 at 8:06 p.m. Another northern sky pass but the station fades away into Earth’s shadow below the North Star.
Thursday Oct. 18 at 7:17 p.m. across the north
Friday Oct. 19 at 8:05 p.m. in the north. Fades away again beneath the North Star
Saturday Oct. 20 at 7:15 p.m. Yet another northern sky pass
Sunday Oct. 21 at 8:03 p.m. in the north and fading beneath the North Star

Draconid meteors busting out all over!

A falling meteor leaves a trail of light as well as one of electrons that radar can “see”. Credit: NASA

There’s a dragon on fire and he’s burning up the sky!

The Draconid meteor shower, underway since this weekend and normally a weak shower, suddenly spiked today around 11 a.m. (CDT). The Canadian Meteor Orbit Radar (CMOR), which “sees” meteors by the tracks of ionized air trails they leave in the upper atmosphere, is recording rates of 1000 per hour. That’s much higher than last year’s outburst and off the charts of this year’s expectations.

Since radar picks up even small meteors that go unnoticed with the naked eye, it’s not known whether all of these would be visible in a dark sky. But, hey, it’s easy enough to go out and have a look for yourself. This afternoon, European observers are favored, since it’s already night there. If you live in the U.S. or Canada , take a look this evening as soon as it gets dark. Face west or north for the best view and cross your fingers the storm continues.

Incoming meteors move so rapidly they knock electrons off air molecules. Turns out you can bounce radio waves off electrons like a ball off a wall. That’s why radar is an excellent tool for “watching” a meteor shower even in daylight.

Here’s a link to a live audio site featuring the sounds of meteors picked up by the Air Force Space Surveillance Radar in Texas. Meteors sound like descending whistles of various pitches. I can’t guarantee the particular meteors you hear are Draconids, but if your sky is cloudy like mine tonight, at least you can still be there.

Unique UK meteor proves what goes around comes around

Video of the September 21, 2012 UK fireball. At closest, the meteor was only 33 miles above the Earth’s surface.
On the evening of September 21 a spectacular fireball as bright as the full moon blazed over the British Isles fracturing into dozens of fragments. Traveling at 8 miles per second – barely enough to escape Earth’s gravity – the meteor took an estimated 3 minutes to cross the sky as it sizzled westward over the Atlantic. Because it lingered so long, some observers thought it might be the breakup of a satellite, but the great majority of satellites travel the opposite direction – from west to east – making a chunk of slow-moving space debris the better possibility. Most meteors strike the atmosphere between 11 and 72 miles per second.

A similar Earth-grazing meteoroid / fireball streaked over Wyoming on August 10, 1972 that came as close as 35 miles before skipping back into space. See video below. Credit and copyright: Antarctic Search for Meteorites program, Case Western Reserve University, James M. Baker

155 minutes later another fireball tore across eastern U.S. and Canadian skies before incinerating itself. Were these two sightings connected? Esko Lyytinen, mathematician and member of the Finnish Fireball Working Group of the Ursa Astronomical Associationmodeled the meteor’s flight and determined that its slow speed may have allowed it to be captured by Earth’s gravity.

After its British debut, the object orbited once around the Earth and flared to life again over Canada before finally breaking to bits. It’s unknown if pieces survived to land as meteorites. The original meteoroid, the name given a space rock before it enters our atmosphere, is estimated to have weighed from several to tens of tons. Most of it would have burned up miles high, turned to dust and vapor by the heat and stress of entry.

Footage of the Great Daylight Fireball of 1972
While pieces of the meteor did burn up over the North Atlantic, Lyytinen believes a surviving fragment skipped back into space to become a temporary satellite of Earth. Slowed to 5.7 miles per second by its atmospheric encounter, the meteoroid’s fate was sealed – it wasn’t going anywhere but down. After one orbit, it flared a final farewell in a fiery trail over Canada.

Frame grab of the Sept. 21 UK fireball. Click to see video. Credit: CCTV / Youtube

Lyttinen cautions that more study needs to be done to confirm his hypothesis. If proven true, this would be the first time a meteoroid has been observed to graze in and out of Earth’s atmosphere, becoming a temporary natural satellite in the process. For a brief few hours our planet had not one but two moons!

I wish to thank Dirk Ross and his excellent Latest Worldwide Meteor / Meteorite News website for background on the fall. Check out his site as well as science writer Kelly Beatty’s .informative article. Stay tuned for an update.

Don’t miss the Perseids, the year’s best meteor shower

The photo NASA doesn’t want you to see. Looks like the wrong time and place AGAIN for the wicked witch of the east.

Mars has so dominated astronomy news this week, it might be easy to ignore everything else in the sky. I’m here to tell you to put the coffee on for the year’s best meteor shower. Yep, you guessed it – the annual Perseids (PURR-see-ids) are back!

The Perseids stand out in several ways: they happen in August when the weather’s nice, they’re rich with meteors –  typically around one a minute – and this year the shower reaches it maximum on Saturday night, when you’re planning on staying up late anyway. Right?

The Perseid meteor shower peaks this Saturday night – Sunday morning. Meteors will appear to shoot out of a spot in the northeastern sky in the constellation Perseus below Cassiopeia. Maps created with Stellarium

The best viewing starts late Saturday night August 11 with the peak coming just before dawn Sunday morning when Perseus – the constellation from which the shower originates – is high in the northeastern sky.

Although the published rate for the Perseids is around 100 per hour, most of us won’t see that many. That number was determined by dedicated meteor shower watchers observing under ideal conditions. For casual viewing under suburban skies you might see between 30 and 60 per hour. That’s plenty!

The thick crescent moon rises around 1:30 a.m. Sunday morning in Taurus near brilliant Jupiter. It won’t be bright or high enough to affect meteor watching. The map shows the sky facing northeast at about 2:30 a.m. local time.

Find a place away from glary lights to allow your eyes to adapt to the darkness. That way you’ll see many more meteors. While the Perseids spit out the occasional fireball, most shower members are going to be closer in brightness to the stars of the Big Dipper. Lots leave these cool “smoke” trails called meteor trains. They’re actually tubes of glowing air molecules created as the meteoroid particles charge in the atmosphere from outer space at an average speed of 130,000 miles per hour 50 to 70 miles over our heads.

Since the meteors appear to radiate from Perseus, the higher the constellation rises, the higher the radiant gets and the more meteors will show above your horizon. That’s why those who stay up late will get more goodies. To view the shower all you need are your eyes and a comfortable chair. Set up facing to the east or southeast with Perseus off to your left. Sit back, look up and enjoy.

A Perseid meteor, remnant of Comet Swift-Tuttle, burns up to the left of the Milky Way during a past shower. Credit: Kevin Clifford/AP

The Perseids are the left-behind sand, seed and pebble-sized particles from comet 109P/Swift-Tuttle. Discovered in 1862, it circles the sun every 120 years. Over millenia, the comet has left a stream of debris along its orbit which the Earth passes through every year in mid-August. The little comet crunchies hit our atmospheric ‘windshield’ like bugs smacking a car’s windshield and vaporize in a flash of light we call a meteor or shooting star.

A Perseid meteor captured from one of the windows in the International Space Station last August. Credit: NASA

While shower maximum occurs the morning of August 12, you’ll still see a fair number of meteors Friday night and Sunday night, so don’t pass on the event if your weather’s poor Saturday. Check your local forecast HERE.

Call a friend or coax a family member to stay up late this weekend to enjoy the show. Not only will you see meteors, the space station is making evening passes across North America and the crescent moon will be near the brilliant planets Jupiter and Venus. Speaking of the moon, it rises around 1:30 a.m. local time Sunday morning and should have little effect on the shower, since it’s neither too bright nor too high.

Meteor activity ticks up, helps spawn extraterrestrial clouds on Earth

Bright fireball meteor captured from Dayton, Ohio on video camera by John Chumack on August 1.

Meteor activity’s been picking up in recent days as we approach the maximum of the Perseid shower, one of the year’s best. Astrophotographer John Chumack of Ohio has recorded plenty of bright meteors, even fireballs, on his nighttime video camera this past week.

Earth bumped into its first Perseids starting the last week of July with the peak of the shower expected next Saturday night-Sunday morning August 11-12. Expect to see at least one a minute under dark skies.

Lots of other minor showers are active in early August including the Northern Delta Aquarids, Alpha Capricornids, Kappa Cygnids and Iota Aquarids. Individually each amounts to little, but taken together they make the sky busier than normal with shooting stars.

The fuzzy streak to the left of the meteor is an expanding cloud of meteoric dust. Credit: John Chumack

Meteors come from meteoroids, small bits of dust and rock ranging carrot seed size to small pebbles.  When a meteoroid strikes Earth’s atmosphere 50-70 miles overhead it burns in a flash to create a meteor. It also leaves behind a trail of minute dust particles or soot called meteoric smoke.

In a recent article published in the Journal of Atmospheric and Solar-Terrestrial Physics, researcher Dr. Mark Hervig used data from NASA’s orbiting AIM spacecraft to discover that meteoric smoke is responsible for seeding noctilucent clouds, those wispy blue curls that appear low in the northern sky during twilight.

AIM or Aeronomy of Ice in the Mesosphere is the first mission dedicated to study noctilucent clouds (also called Polar Mesospheric Clouds) to figure out why they form and whether they might be connected to climate change.

Noctilucent clouds glow pale blue during evening and morning twilight at northerly latitudes during the summer months. They’re about 50 miles high and made of ice crystals and a smidge of meteor smoke. Photo: Bob King

To build a cloud, whether mesospheric or a puffy summertime cumulus, you need dust, soot or some type of particle for water or ice to condense around. The dust forms the nucleus of each raindrop or ice crystal; molecules of water latch onto it and assemble into a crystal in a process called nucleation.

Using data from AIM’s Solar Occultation For Ice Experiment (SOFIE) and comparing it to simulated mixtures of ice and meteoric smoke, Hervig found that up to 3 percent of the material in the ice crystals in noctilucent clouds was dust deposited by meteors. This makes perfect sense when you consider that meteors burn up at the same altitude the cloud form.

Looking down from above, AIM captured this composite image of the noctilucent cloud cover above the south pole on December 31, 2009. Credit: NASA/HU/VT/CU LASP

AIM found the ice crystals were only 20 to 70 billionths of a meter or 20 to 70 nanometers across. That’s tiny! A sheet of paper is 100,000 nanometers thick, and the ice crystals in a typical cirrus cloud are 250,000 nanometers long. Their small size makes them very good at scattering the short-wavelength blue portion of sunlight back to our eyes. That’s how noctilucent clouds  get their distinctive color.

Noctilucents used to be visible only at high northern and southern latitudes. Not only have they been on the increase since the 20th century but they’ve occasionally spread as far south as Colorado and Utah. Scientists think these changes are due to an increase of methane gas from human activities like coal mining, agriculture and natural gas plants. The methane rises into the upper atmosphere, where it’s transformed by chemical reactions into water vapor. The extra water available provides the raw material for creating more noctilucent clouds.

I feel torn. Watching meteors slingshot across the sky this month, we can relish the knowledge that the dust they drop goes to build clouds in part extraterrestrial. At the same time it’s unsettling that their lushness may have much to do with us.

Delta Aquarid meteor shower fires up for the weekend

Meteors from southern Delta Aquarid meteor shower radiate from near the star Delta Aquarii (hence the name) not far from the bright star Fomalhaut in the Southern Fish low in the south before dawn. Created with Stellarium

It’s not a big shower, especially for the northern half of the planet, but if you’re up late this weekend and attentive, you’ll see more meteors than usual flashing across the sky. The annual Delta Aquarid meteor shower crests to a maximum tomorrow and Sunday mornings with 10-15 meteors per hour visible from a dark sky site.

Sky watchers in the southern hemisphere will see double that because the radiant, the point from which the meteors originate, is much higher in the sky. Meteors barreling down the sky south of the radiant don’t get cut off by the horizon.

When Earth’s orbit intersects rocky and icy debris left in the wake of comet tail, we experience a meteor shower. Illustration: Bob King

There are actually two meteor showers in Aquarius active this time of year – the northern and southern Delta Aquarids. The northern version sports fewer meteors and peaks in mid-August.

Both are very broad streams. Tomorrow’s southern “Deltas” started in mid-July and will peter out a month later. This weekend marks the peak.

Nearly all meteor showers originate from clouds of sand to seed-sized bits of debris fizzed off by comets as they swing near the sun. As a candy lover, I  like the image of Tootsie-Rolls tossed out at a parade.

Earth plows into these debris streams at specific times each year, creating a shower of meteors from the sky. Those bits of comet dust strike the air overhead at many thousands of miles an hour, burning up in a flash we call a meteor. Energy imparted to the air molecules by the speeding particles is converted into the light we see streaking across the sky.

A meteor from the April Lyrid shower burns up in the atmosphere some 70 miles high as seen from the International Space Station. Credit: NASA

The best time to watch the Delta Aquarids is in the early morning hours before dawn when the radiant is up in the southeastern sky. Happily, the gibbous moon will set around 1 a.m., leaving dark skies during the ideal viewing time. Find a spot with a good view to the south and set up a lawn chair. You don’t need any other equipment than your eyes … and maybe a cup or two of coffee. The Aquarids will whet your appetite for the bigger, better Perseid meteor show coming to Earth on Saturday night August 11-12.

Since most showers have a “parent” comet, you might be interested to know that the likely one for the Delta Aquarids is none other than 96P/Machholz. Yes, the very same comet that’s currently visible in medium-sized scopes low in the western sky during evening twilight. How nice to meet the artist and admire his work at the same time.