Meteors Archives

November 14, 2013December 23, 2015 by David Dickinson

Here Comes the Weekend Leonid Meteor Shower!

November 2013 offers a chance to catch a dependable meteor shower, albeit on an off year. The Leonid meteors are set to reach their annual peak this coming weekend on Sunday, November 17th. We say it’s an off-year, but not that it should discourage you from attempting to catch the Leonids this weekend in the early dawn.

Projections for 2013 suggest a twin-peaked maximum, with the first peak arriving on November 17^th at 10:00 UT/5:00 AM EST favoring North America, and the second one reaching Earth on the same date six hours later at 16:00 UT/11:00, favoring the central Pacific.

Unfortunately, the Full Moon also occurs the on very date that the Leonids peak at 10:16 AM EST/ 15:16UT, right between the two peaks! This will definitely cut down on the number of meteors you’ll see in the early AM hours.

That’s strike one against the 2013 Leonids. The next is the curious sporadic nature of this shower. Normally a minor shower with a zenithal hourly rate (ZHR) in the range of 10-20 per hour, the Leonids are prone to great storms topping a ZHR of 1,000+ every 33 years. We last experienced such an event in 1998 and 1999, and we’re now approaching the mid-point lull between storms in the 2014-2016 time frame.

An early Leonid meteor captured last week from the United Kingdom Meteor Observing Network's Church Crookham station. (Credit: UKMON/Peter-Campbell-Burns). — An early Leonid meteor captured last week from the United Kingdom Meteor Observing Network’s Church Crookham station. (Credit: UKMON/Peter-Campbell-Burns).

Still, this is one shower that’s always worth monitoring. The source of the Leonids is Comet 55p/Tempel-Tuttle, which is on a 33-year orbit and is due to reach perihelion again in 2031.

Note that the Leonids have also continued to show enhanced activity in past years even when the Moon was a factor:

2012- ZHR=47.

2011- ZHR=22, Moon=8% waning gibbous.

2010- ZHR=40, 86% waxing gibbous.

2009- ZHR=79.

2008-70 ZHR=72% waning gibbous

We even managed to observe the Leonid meteors from Vail, Arizona in 2002 and 2005, on years when the Moon was nearly Full.

Now, for the good news. The Leonids have a characteristic r value of 2.5, meaning that they produce a higher than normal ratio of fireballs. About 50-70% of Leonid meteors are estimated to leave persistent trains, a good reason to keep a pair of binoculars handy. And hey, at least the 2013 Leonids peak on the weekend, and there’s always comet’s ISON, X1 LINEAR, 2P/Encke and R1 Lovejoy to track down to boot!

A 2002 Leonid captured over Redstone Arsenal, Alabama. (Credit: NASA/MSFC/MEO/Bill Cooke).

Here’s a few tips and tricks that you can use to “beat the Moon” on your Leonid quest. One is to start observing now, on the moonless mornings leading up to the 17^th. You’ll always see more Leonid meteors past local midnight as the radiant rises to the northeast. This is because you’re standing on the portion of the Earth turning forward into the meteor stream. Remember, the front windshield of your car (the Earth) always collects the most bugs (meteors). Observers who witnessed the 1966 Leonid storm reported a ZHR in excess of thousands per hour, producing a Star Trek-like effect of the Earth plowing through a “snowstorm” of meteors!

The radiant of the Leonids sits in the center of the backwards question mark asterism of the “Sickle” in the astronomical constellation Leo (hence name of the shower).

You can also improve your prospects for seeing meteors by blocking the Moon behind a building or hill. Though the Leonids will appear to radiate from Leo, they can appear anywhere in the sky. Several other minor showers, such as the Taurids and the Monocerotids, are also active in November.

Meteor shower photography is simple and can be done with nothing more than a DSLR camera on a tripod. This year, you’ll probably want to keep manual exposures short due to the Full Moon and in the 20 seconds or faster range. Simply set the camera to a low f-stop/high ISO setting and a wide field of view and shoot continuously. Catching a meteor involves luck and patience, and be sure to examine the frames after a session; every meteor I’ve caught on camera went unnoticed during observation! Don’t be afraid to experiment with different combinations to get the sky conditions just right. Also, be sure to carry and extra set of charged camera batteries, as long exposures combined with chilly November mornings can drain DSLR batteries in a hurry!

A Woodcut print depicting the 1933 Leonids as seem from Niagara Falls. (Wikimedia Commons image in the Public Domian). — A Woodcut print depicting the 1933 Leonids as seem from Niagara Falls. (Wikimedia Commons image in the Public Domain).

The Leonids certainly have a storied history, dating back to before meteors where understood to be dust grains left by comets. The 1833 Leonids were and awesome and terrifying spectacle to those who witnessed them up and down the eastern seaboard of the U.S. In fact, the single 1833 outburst has been cited as contributing to the multiple religious fundamentalist movements that cropped up in the U.S. in the 1830s.

We witnessed the 1998 Leonids from the deserts of Kuwait while stationed at Al Jabber Air Base. It was easily one of the best meteor displays we ever saw, with a ZHR reaching in access of 500 per hour before dawn. It was intense enough that fireballs behind us would often light up the foreground like camera flashes!

Reporting rates and activity for meteor showers is always fun and easy to do — its real science that you can do using nothing more than a stopwatch and your eyes. The International Meteor Association is always looking for current meteor counts from observers. Data goes towards refining our understanding and modeling of meteor streams and future predictions. The IMO should also have a live ZHR graph for the 2013 Leonids running soon.

Have fun, stay warm, send those Leonid captures in to Universe Today, and don’t forget to tweet those meteors to #Meteorwatch!

November 7, 2013December 23, 2015 by Bob King

Newly Released Security Cam Video Shows Chelyabinsk Meteorite Impact in Lake Chebarkul

The 20-foot (6-meter) hole punched through the ice on Chebarkul Lake by a large fragment of the Chelyabinsk meteorite. Credit: AP

Security camera video showing the impact of the largest piece of the Chelyabinsk meteorite striking Lake Chebarkul during the Feb. 15, 2013 Russian fireball. Credit: Nikolaj Mel’nikov.

When I first watched this video of the half-ton Chelyabinsk meteorite crashing into Lake Chebarkul last Feb. 15 I didn’t see anything. But once you pay close attention, what you’ll see is nothing short of amazing. You’ll recall that a 20-foot (6 meter) hole appeared in the ice immediately after the fall. While no one witnessed the impact, a security camera caught the critical moment from the other side of the lake.

The video recently appeared in an online presentation by Peter Jenniskens, noted meteorite expert and senior research scientist at the SETI Institute. It was released as part of a paper and Powerpoint on the Chelyabinsk airburst. You can listen to Jenniskens’ presentation HERE.

*Frame grab from the video showing the breakdown of the impact and resulting ice and snow cloud.*

When you watch the video, focus your attention just to the left of what looks like an ice fishing shack at top center and use the handy frame grab above. In the slowed-down portion of the footage you’ll see a cloud of ice and snow blow up and quickly drift to the right of the shack seconds after impact. While blurry and small, it’s amazing good fortune we have a document of this fall.

Video of the recovery of the largest piece of the Chelyabinsk meteorite

Divers ultimately fished the 1/2 ton Chelyabinsk meteorite – the largest found so far – from the lake on Oct. 16. It measured 5 feet long (1.5 meter) and broke into three pieces as scientists hoisted it into a scale to weigh it.

As a return favor, the little piece of heaven broke the scale.

October 16, 2013December 23, 2015 by Elizabeth Howell

Possible Huge Meteorite Fragment Recovered From Russian Fireball

Frame grab from a video of the Feb. 15, 2013 Russian fireball by Aleksandr Ivanov

A half-ton meteorite — presumably from the Russian fireball that broke up over Chelyabinsk in February — was dragged up from Lake Chebarkul in the Urals, Russian media reports said. Scientists estimate the chunk is about 1,260 pounds (570 kilograms), but couldn’t get a precise measurement in the field because the bulky bolide broke the scale, according to media reports.

“The preliminary examination… shows that this is really a fraction of the Chelyabinsk meteorite,” said Sergey Zamozdra, associate professor of Chelyabinsk State University, in reports from Interfax and RT.

A polished slice of one of Russian meteorite samples. You can see round grains called chondrules and shock veins lined with melted rock. The meteorite is probably non-uniform. The preliminary analysis showed that the meteorite belongs to chemical type L or LL, petrologic type 5. — A polished slice of one of Russian meteorite samples (different samples than what was reportedly recovered on Oct. 16). You can see round grains called chondrules and shock veins lined with melted rock. The meteorite is probably non-uniform. The preliminary analysis showed that the meteorite belongs to chemical type L or LL, petrologic type 5.

“It’s got thick burn-off, the rust is clearly seen and it’s got a big number of indents. This chunk is most probably one of the top ten biggest meteorite fragments ever found.”

The big rock was first spotted in September, but it’s taken several attempts to bring it to the surface. If scientists can confirm this came from the fireball, this would be the biggest piece recovered yet. The chunk is reportedly in a natural history museum, where a portion will be X-rayed to determine its origins.

More than 1,000 people were injured and millions of dollars in damage occurred when the meteor broke up in the atmosphere Feb. 15, shattering glass and causing booms.

Since then, there have been numerous papers concerning the meteor’s origins (from the Apollo class of asteroids — you can read this article if you’re unclear on the difference between an asteroid and a meteorite) and tracking the spread of dust through the atmosphere, among other items.

August 30, 2013December 23, 2015 by Ken Kremer

Are We Martians? Chemist’s New Claim Sparks Debate

Are Earthlings really Martians ?
Did life arise on Mars first and then journey on rocks to our planet and populate Earth billions of years ago? Earth and Mars are compared in size as they look today. NASA’s upcoming MAVEN Mars orbiter is aimed at answering key questions related to the habitability of Mars, its ancient atmosphere and where did all the water go.
Story updated[/caption]

Are Earthlings really Martians?

That’s the controversial theory proposed today (Aug. 29) by respected American chemist Professor Steven Benner during a presentation at the annual Goldschmidt Conference of geochemists being held in Florence, Italy. It’s based on new evidence uncovered by his research team and is sure to spark heated debate on the origin of life question.

Benner said the new scientific evidence “supports the long-debated theory that life on Earth may have started on Mars,” in a statement. Universe Today contacted Benner for further details and enlightenment.

“We have chemistry that (at least at the level of hypothesis) makes RNA prebiotically,” Benner told Universe Today. “AND IF you think that life began with RNA, THEN you place life’s origins on Mars.” Benner said he has experimental data as well.

First- How did ancient Mars life, if it ever even existed, reach Earth?

On rocks violently flung up from the Red Planet’s surface during mammoth collisions with asteroids or comets that then traveled millions of miles (kilometers) across interplanetary space to Earth – melting, heating and exploding violently before the remnants crashed into the solid or liquid surface.

An asteroid impacts ancient Mars and send rocks hurtling to space - some reach Earth — An asteroid impacts ancient Mars and send rocks hurtling to space – some reach Earth. Did they transport Mars life to Earth? Or minerals that could catalyze the origin of life on Earth?

“The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock,” says Benner, of The Westheimer Institute of Science and Technology in Florida. That theory is generally known as panspermia.

To date, about 120 Martian meteorites have been discovered on Earth.

And Benner explained that one needs to distinguish between habitability and the origin of life.

“The distinction is being made between habitability (where can life live) and origins (where might life have originated).”

NASA’s new Curiosity Mars rover was expressly dispatched to search for environmental conditions favorable to life and has already discovered a habitable zone on the Red Planet’s surface rocks barely half a year after touchdown inside Gale Crater.

Furthermore, NASA’s next Mars orbiter- named MAVEN – launches later this year and seeks to determine when Mars lost its atmosphere and water- key questions in the Origin of Life debate.

Curiosity accomplished Historic 1st drilling into Martian rock at John Klein outcrop on Feb 8, 2013 (Sol 182) and discovered a habitable zone, shown in this context mosaic view of the Yellowknife Bay basin taken on Jan. 26 (Sol 169). The robotic arm is pressing down on the surface at John Klein outcrop of veined hydrated minerals – dramatically back dropped with her ultimate destination; Mount Sharp. Credit: NASA/JPL-Caltech/Ken Kremer-kenkremer.com/Marco Di Lorenzo

Of course the proposed chemistry leading to life is exceedingly complex and life has never been created from non-life in the lab.

The key new points here are that Benner believes the origin of life involves “deserts” and oxidized forms of the elements Boron (B) and Molybdenum (Mo), namely “borate and molybdate,” Benner told me.

“Life originated some 4 billion years ago ± 0.5 billon,” Benner stated.

He says that there are two paradoxes which make it difficult for scientists to understand how life could have started on Earth – involving organic tars and water.

Life as we know it is based on organic molecules, the chemistry of carbon and its compounds.

But just discovering the presence of organic compounds is not the equivalent of finding life. Nor is it sufficient for the creation of life.

And simply mixing organic compounds aimlessly in the lab and heating them leads to globs of useless tars, as every organic chemist and lab student knows.

Benner dubs that the ‘tar paradox’.

Although Curiosity has not yet discovered organic molecules on Mars, she is now speeding towards a towering 3 mile (5 km) high Martian mountain known as Mount Sharp.

Curiosity Spies Mount Sharp - her primary destination. Curiosity will ascend mysterious Mount Sharp and investigate the sedimentary layers searching for clues to the history and habitability of the Red Planet over billions of years. This mosaic was assembled from over 3 dozen Mastcam camera images taken on Sol 352 (Aug 2, 2013. Credit: NASA/JPL-Caltech/MSSS/ Marco Di Lorenzo/Ken Kremer — Curiosity Spies Mount Sharp – her primary destination
Curiosity will ascend mysterious Mount Sharp and investigate the sedimentary layers searching for clues to the history and habitability of the Red Planet over billions of years. This mosaic was assembled from over 3 dozen Mastcam camera images taken on Sol 352 (Aug 2, 2013. Credit: NASA/JPL-Caltech/MSSS/ Marco Di Lorenzo/Ken Kremer-kenkremer.com

Upon arrival sometime next spring or summer, scientists will target the state of the art robot to investigate the lower sedimentary layers of Mount Sharp in search of clues to habitability and preserved organics that could shed light on the origin of life question and the presence of borates and molybdates.

It’s clear that many different catalysts were required for the origin of life. How much and their identity is a big part of Benner’s research focus.

“Certain elements seem able to control the propensity of organic materials to turn into tar, particularly boron and molybdenum, so we believe that minerals containing both were fundamental to life first starting,” says Benner in a statement. “Analysis of a Martian meteorite recently showed that there was boron on Mars; we now believe that the oxidized form of molybdenum was there too.”

The second paradox relates to water. He says that there was too much water covering the early Earth’s surface, thereby causing a struggle for life to survive. Not exactly the conventional wisdom.

“Not only would this have prevented sufficient concentrations of boron forming – it’s currently only found in very dry places like Death Valley – but water is corrosive to RNA, which scientists believe was the first genetic molecule to appear. Although there was water on Mars, it covered much smaller areas than on early Earth.”

Parts of ancient Mars were covered by oceans, lakes and streams of liquid water in this artists concept, unlike the arid and bone dry Martian surface of today. Subsurface water ice is what remains of Martian water.

I asked Benner to add some context on the beneficial effects of deserts and oxidized boron and molybdenum.

“We have chemistry that (at least at the level of hypothesis) makes RNA prebiotically,” Benner explained to Universe Today.

“We require mineral species like borate (to capture organic species before they devolve to tar), molybdate (to arrange that material to give ribose), and deserts (to dry things out, to avoid the water problem).”

“Various geologists will not let us have these [borates and molybdates] on early Earth, but they will let us have them on Mars.”

“So IF you believe what the geologists are telling you about the structure of early Earth, AND you think that you need our chemistry to get RNA, AND IF you think that life began with RNA, THEN you place life’s origins on Mars,” Benner elaborated.

“The assembly of RNA building blocks is thermodynamically disfavored in water. We want a desert to get rid of the water intermittently.”

I asked Benner whether his lab has run experiments in support of his hypothesis and how much borate and molybdate are required.

“Yes, we have run many lab experiments. The borate is stoichiometric [meaning roughly equivalent to organics on a molar basis]; The molybdate is catalytic,” Benner responded.

“And borate has now been found in meteorites from Mars, that was reported about three months ago.

At his talk, Benner outlined some of the chemical reactions involved.

Although some scientists have invoked water, minerals and organics brought to ancient Earth by comets as a potential pathway to the origin of life, Benner thinks differently about the role of comets.

“Not comets, because comets do not have deserts, borate and molybdate,” Benner told Universe Today.

The solar panels on the MAVEN spacecraft are deployed as part of environmental testing procedures at Lockheed Martin Space Systems in Littleton, Colorado, before shipment to Florida 0on Aug. 2 and blastoff for Mars on Nov. 18, 213. Credit: Lockheed Martin — MAVEN is NASA’s next Mars orbiter and seeks to determine when Mars lost its atmosphere and water- key questions in the Origin of Life debate. MAVEN is slated to blastoff for Mars on Nov. 18, 2013. It is shown here with solar panels deployed as part of environmental testing procedures at Lockheed Martin Space Systems in Waterton, Colorado, before shipment to Florida in early August. Credit: Lockheed Martin

Benner has developed a logic tree outlining his proposal that life on Earth may have started on Mars.

“It explains how you get to the conclusion that life originated on Mars. As you can see from the tree, you can escape that conclusion by diverging from the logic path.”

Finally, Benner is not one who blindly accepts controversial proposals himself.

He was an early skeptic of the claims concerning arsenic based life announced a few years back at a NASA sponsored press conference, and also of the claims of Mars life discovered in the famous Mars meteorite known as ALH 84001.

“I am afraid that what we thought were fossils in ALH 84001 are not.”

The debate on whether Earthlings are really Martians will continue as science research progresses and until definitive proof is discovered and accepted by a consensus of the science community of Earthlings – whatever our origin.

On Nov. 18, NASA will launch its next mission to Mars – the MAVEN orbiter. Its aimed at studying the upper Martian atmosphere for the first time.

“MAVENS’s goal is determining the composition of the ancient Martian atmosphere and when it was lost, where did all the water go and how and when was it lost,” said Bruce Jakosky to Universe Today at a MAVEN conference at the University of Colorado- Boulder. Jakosky, of CU-Boulder, is the MAVEN Principal Investigator.

MAVEN will shed light on the habitability of Mars billions of years ago and provide insight on the origin of life questions and chemistry raised by Benner and others.

Ken Kremer

…………….
Learn more about Mars, the Origin of Life, LADEE, Cygnus, Antares, MAVEN, Orion, Mars rovers and more at Ken’s upcoming presentations

Sep 5/6/16/17: “LADEE Lunar & Antares/Cygnus ISS Rocket Launches from Virginia”; Rodeway Inn, Chincoteague, VA, 8 PM

Oct 3: “Curiosity, MAVEN and the Search for Life on Mars – (3-D)”, STAR Astronomy Club, Brookdale Community College & Monmouth Museum, Lincroft, NJ, 8 PM

Oct 9: “LADEE Lunar & Antares/Cygnus ISS Rocket Launches from Virginia”; Princeton University, Amateur Astronomers Assoc of Princeton (AAAP), Princeton, NJ, 8 PM

August 28, 2013December 23, 2015 by Elizabeth Howell

Russian Meteor Experienced Melting Before Slamming Into Earth: Study

The two main smoke trails left by the Russian meteorite as it passed over the city of Chelyabinsk. Credit: AP Photo/Chelyabinsk.ru

A collision or “near miss” caused melting in the Chelyabinsk meteor before it slammed into Earth’s atmosphere this February, causing damage and injuries to hundreds in the remote Russian region.

A new study, presented at the Goldschmidt Conference in Florence, Italy, says some meteorite fragments’ composition shows strong evidence of heating, which is an indication of interplanetary violence of some sort.

“The meteorite which landed near Chelyabinsk is a type known as an LL5 chondrite, and it’s fairly common for these to have undergone a melting process before they fall to Earth,” stated Victor Sharygin, a researcher from the Sobolev Institute of Geology and Mineralogy in Russia.

“This almost certainly means that there was a collision between the Chelyabinsk meteorite and another body in the solar system, or a near miss with the Sun.”

Chelyabinsk’s size of 59 feet (18 meters) was by no means a very large meteor, but it was enough to cause car alarms to go off and to shatter glass when it exploded over Russia on Feb. 15. Its arrival brought the danger of space rocks once again to public attention.

In just the few short months since its arrival, a number of research studies have begun to sketch out its origins and effects. One recent NASA study showed that the cloud of dust from the explosion spread around the northern hemisphere in days.

Sharygin’s team analyzed several fragments of the meteorites and put them into three groups: light, dark and intermediate. Lights ones were the most abundant. Dark fragments were most commonly found in the area where the meteorite hit the Earth.

While only three of the dark fragments show there was previous melting, the researchers say it’s quite possible that more samples might be available from the public and most notably, from the main portion that is still at the bottom of Chebarkul Lake.

“The dark fragments include a large proportion of fine-grained material, and their structure, texture and mineral composition shows they were formed by a very intensive melting process,” a press release stated.

“This material is distinct from the ‘fusion crust’ – the thin layer of material on the surface of the meteorite that melts, then solidifies, as it travels through the Earth’s atmosphere.”

A "fusion crust" or melting is visible in this fragment of the Chelyabinsk meteorite. Credit: Victor Sharygin — A “fusion crust” or melting is visible in this fragment of the Chelyabinsk meteorite. Credit: Victor Sharygin

Researchers also spotted “bubbles” in the dark fragments that they consider either “perfect crystals” of oxides, silicates and metal or little spots that are filled up with sulfide or metal.

They also saw platinum-type elements in the crust, which was a surprise as the time it takes for a crust to fuse is too short for platinum to form.

“We think the appearance (formation) of this platinum group mineral in the fusion crust may be linked to compositional changes in metal-sulfide liquid during remelting and oxidation processes as the meteorite came into contact with atmospheric oxygen,” Sharygin stated.

The work is ongoing, and no submission date for a study for publication was disclosed.

Source: EurekAlert!

August 14, 2013December 23, 2015 by Nancy Atkinson

Satellite Watches Dust from Chelyabinsk Meteor Spread Around the Northern Hemisphere

When a meteor weighing 10,000 metric tons exploded 22.5 km (14 miles) above Chelyabinsk, Russia on Feb. 15, 2013, the news of the event spread quickly around the world. But that’s not all that circulated around the world. The explosion also deposited hundreds of tons of dust in Earth’s stratosphere, and NASA’s Suomi NPP satellite was in the right place to be able to track the meteor plume for several months. What it saw was that the plume from the explosion spread out and wound its way entirely around the northern hemisphere within four days.

The bolide, measuring 59 feet (18 meters) across, slipped quietly into Earth’s atmosphere at 41,600 mph (18.6 kilometers per second). When the meteor hit the atmosphere, the air in front of it compressed quickly, heating up equally as quick so that it began to heat up the surface of the meteor. This created the tail of burning rock that was seen in the many videos that emerged of the event. Eventually, the space rock exploded, releasing more than 30 times the energy from the atom bomb that destroyed Hiroshima. For comparison, the ground-impacting meteor that triggered mass extinctions, including the dinosaurs, measured about 10 km (6 miles) across and released about 1 billion times the energy of the atom bomb.

Atmospheric physicist Nick Gorkavyi from Goddard Space Flight Center, who works with the Suomi satellite, had more than just a scientific interest in the event. His hometown is Chelyabinsk.

“We wanted to know if our satellite could detect the meteor dust,” said Gorkavyi, who led the study, which has been accepted for publication in the journal Geophysical Research Letters. “Indeed, we saw the formation of a new dust belt in Earth’s stratosphere, and achieved the first space-based observation of the long-term evolution of a bolide plume.”

The team said they have now made unprecedented measurements of how the dust from the meteor explosion formed a thin but cohesive and persistent stratospheric dust belt.

About 3.5 hours after the initial explosion, the Ozone Mapping Profiling Suite instrument’s Limb Profiler on the NASA-NOAA Suomi National Polar-orbiting Partnership satellite detected the plume high in the atmosphere at an altitude of about 40 km (25 miles), quickly moving east at about 300 km/h (190 mph).

The day after the explosion, the satellite detected the plume continuing its eastward flow in the jet and reaching the Aleutian Islands. Larger, heavier particles began to lose altitude and speed, while their smaller, lighter counterparts stayed aloft and retained speed – consistent with wind speed variations at the different altitudes.

By Feb. 19, four days after the explosion, the faster, higher portion of the plume had snaked its way entirely around the Northern Hemisphere and back to Chelyabinsk. But the plume’s evolution continued: At least three months later, a detectable belt of bolide dust persisted around the planet.

Gorkavyi and colleagues combined a series of satellite measurements with atmospheric models to simulate how the plume from the bolide explosion evolved as the stratospheric jet stream carried it around the Northern Hemisphere.

“Thirty years ago, we could only state that the plume was embedded in the stratospheric jet stream,” said Paul Newman, chief scientist for Goddard’s Atmospheric Science Lab. “Today, our models allow us to precisely trace the bolide and understand its evolution as it moves around the globe.”

NASA says the full implications of the study remain to be seen. Scientists have estimated that every day, about 30 metric tons of small material from space encounters Earth and is suspended high in the atmosphere. Now with the satellite technology that’s capable of more precisely measuring small atmospheric particles, scientists should be able to provide better estimates of how much cosmic dust enters Earth’s atmosphere and how this debris might influence stratospheric and mesospheric clouds.

It will also provide information on how common bolide events like the Chelyabinsk explosion might be, since many might occur over oceans or unpopulated areas.

“Now in the space age, with all of this technology, we can achieve a very different level of understanding of injection and evolution of meteor dust in atmosphere,” Gorkavyi said. “Of course, the Chelyabinsk bolide is much smaller than the ‘dinosaurs killer,’ and this is good: We have the unique opportunity to safely study a potentially very dangerous type of event.”

Source: NASA

August 6, 2013March 16, 2017 by Fraser Cain

What is a Meteor Shower?

When tiny grains of dust impact our atmosphere, they leave a trail of glowing material, like a streak of light across the sky.

This is a meteor, or a shooting star.

On any night, you can go outside, watch the sky, and be guaranteed to see one. Individual meteors start as meteoroids – pieces of rock smaller than a pebble flying around the Solar System.

Even though they’re tiny, these objects can be moving at tens of thousands of kilometers per hour. When they hit Earth’s atmosphere, they release tremendous amounts of energy, burning up above an altitude of 50 kilometers.

As they disintegrate, they leave a trail of superheated gas and rocky sparks which last for a moment in the sky, and then cool down and disappear from view.

Throughout the year there are several meteor showers, when the number of meteors streaking through the sky increases dramatically. This happens when the Earth passes through the trail of dust left by a comet or asteroid.

Meteor showers are when night sky puts on a special show, and it’s a time to gather your friends and family together and enjoy the spectacle.

Some showers produce only a trickle of objects, while others, like the famous Perseid meteor shower, can dependably bring dozens of meteors each hour.

Meteor Burst - Credit: NASA — Meteor Burst – Credit: NASA

If the trail is dense enough, we can get what is called a meteor storm. The most powerful meteor storms in history truly made it look like the sky was falling. The Leonids in 1833 produced hundreds of thousands per hour.

Meteor showers take their name from the constellation from where they appear to originate. For example, the Perseids trace a trail back to the constellation Perseus; although you can see them anywhere across the sky.

You can see meteors any time of the year, and you don’t need any special equipment to enjoy an average meteor shower. But here are some ways you can improve your experience.

You’ll want to find a location with as clear a view to the horizon in as many directions as possible. An open field is great. Lie on your back, or on a reclining chair, look up to the sky

… and be patient.

A bright fireball meteor in twilight. The Lyrids, like all meteor showers, offer up the occasional fireball among a mix of fainter meteors. Credit: John Chumack

You probably won’t see a meteor right away, but after a few minutes, you should see your first one.

The longer you look, the more you’ll see, and the better chance you’ll have of seeing a bolide or fireball; a very bright meteor that streaks across the sky, leaving a trail that can last for a long time.

You can see meteors any time that it’s dark, but the most impressive ones happen in the early morning, when your location on Earth is ploughing directly into the space dust.

You also want the darkest skies you can get, far away from city light pollution, and many hours after the Sun has gone down.

Enjoy the early evening meteors, but then set your alarm and get up around 4 in the morning to see the real sky show.

If I could only see one meteor shower every year, it would have to be the Perseids. These come when the Earth passes through the tail of Comet Swift-Tuttle, and peak around August 12th every year. It’s not always the most active shower, but it’s warm outside in the Northern hemisphere, and this is a fun activity to do with your friends and family.

Now get outside, and enjoy a meteor shower.

August 3, 2013January 22, 2021 by David Dickinson

The 2013 Perseid Meteor Shower: An Observer’s Guide

Get set for the meteoritic grand finale of summer.

Northern hemisphere summer that is. As we head into August, our gaze turns towards that “Old Faithful” of meteor showers, the Perseids. Though summer is mostly behind us now, “meteor shower season” is about to get underway in earnest.

Pronounced “Pur-SEE-ids,” this shower falls around the second week of August, just before school goes back in for most folks. This time of year also finds many the residents of the northern hemisphere out camping and away from light-polluted suburban skies.

This year also offers a special treat, as the Moon will be safely out of the sky during key observation times. The Moon reaches New phase on August 6^th at 5:51 PM EDT/ 9:51 Universal Time (UT) and will be a 32% illuminated waxing crescent around the anticipated peak for the Perseid meteors on August 12^th. And speaking of which, the Perseids are infamous for presenting a double-fisted twin peak in activity. This year, the first climax for the shower is predicted for around 13:00 UT on August 12^th, favoring Hawaii and the North American west coast, and the second peak is set to arrive 13 hours later at 02:00 UT, favoring Europe & Africa.

Nodal crossing for the Perseid stream and Earth’s orbit sits right around 18:00 to 21:00 UT on August 12^th for 2013. The shower derives its name from the constellation Perseus, and has a radiant located near Gamma Persei at right ascension 3 hours 4 minutes and a declination of +58 degrees. Atmospheric velocities for the Perseids are on the high end as meteor showers go, at 59km/sec.

Of course, like with any meteor shower, it’s worth starting to watch a few days prior to the peak date. Although meteor streams like the Perseids have been modeled and mapped over the years, there are still lots of surprises out there. Plus, starting an early vigil is insurance that you at least catch some action in the event that you’re clouded out on game day! Like we mentioned in last week’s post on the Delta Aquarids, the Perseids are already active, spanning a season from July 17^th to August 24^th.

The Zenithal Hourly Rate for the Perseids is generally between 60-100 meteors. The ZHR is the number of meteors you could expect to see during optimal conditions under dark skies with the radiant directly overhead. Rates were enhanced back in the 1990’s, and 2004 saw a ZHR of 200.

The orbit of comet Swift-Tuttle and its intersection near the Earth's orbit. (Created the author using NASA/JPL ephmeris generator). — The orbit of comet Swift-Tuttle and its intersection near the Earth’s orbit. (Created by the author using NASA/JPL ephemerides generator).

The source of the Perseids is comet 109P/Swift-Tuttle. Discovered on July 16^th-19th, 1862 by astronomers Lewis Swift & Horace Tuttle, Swift-Tuttle is on a 133.3 year orbit and last passed through the inner solar system in late 1992. This comet will once again grace our skies in early 2126 AD.

The Perseids are also sometimes referred to as the “tears of St Lawrence,” after the Catholic saint who was martyred on August 10^th, 258 AD. The Perseids have been noted by Chinese astronomers as far back as 36 AD, when it was recorded that “more than 100 meteors flew thither in the morning.” The annual nature of the shower was first described by Belgian astronomer Adolphe Quételet in 1835.

Enhanced rates for the Perseids marked the return of comet Swift-Tuttle in the 1990s. Recent years have seen rates as reported by the International Meteor Organization at a ZHR=175(2009), 91(2010), 58(2011), & a resurgence of a ZHR=122 last year.

Just what will 2013 bring? There’s one truism in meteor observing—you definitely won’t see anything if you do not get out and observe. Meteor shower observing requires no equipment, just clear skies and patience. Watch in the early hours before dawn, when the rates are highest. Meteors can occasionally be seen before midnight, but are marked by lower rates and slow, stately trains across the sky. Some suggest that best viewing is at a 45 degree angle away from the radiant, but we maintain that meteors can appear anywhere in the sky. Pair up with a friend or two and watch in opposite directions to increase your meteor-spotting chances.

We also like to keep a set of binoculars handy to examine those smoke trains left by bright fireballs that may persist seconds after streaking across the sky.

And speaking of which, there has also been some spirited discussion over the past week as to whether or not the Perseids produce more fireballs than any other shower. I certainly remember seeing several memorable fireballs from this shower over the years, although the Geminids, Leonids and Taurids can be just spectacular on active years. The stated r value of the Perseids is one of the lowest at 2.2, suggesting a statistically high percentage of fireballs.

And in the realm of the strange and the curious, here are just a few phenomena to watch/listen for on your Perseid vigil;

– Can you “hear” meteors? Science says that sounds shouldn’t carry through the tenuous atmosphere above 50 kilometres up, and yet reports of audible meteors as a hiss or crackle persist. Is this an eye-brain illusion? Researchers in 1988 actually studied this phenomenon, which is also sometimes reported during displays of aurora. If there’s anything to it, the culprit may be the localized generation of localized electrophonic noises generated by Extra/Very Low Frequency electromagnetic radiation.

– Can meteor streaks appear colored? Green is often the top reported hue.

– Can meteors appear to “corkscrew” during their trajectory, or is this an illusion?

A Perseid very near the shower radiant during the 2012 shower. (Photo by author).

Wide-field photography is definitely a viable option during meteor showers. Just remember to bring extra charged batteries, as long exposure times will drain modern DSLRs in a hurry!

And did you know: you can even “listen” to meteor pings on an FM radio or portable TV? This is a great “rain check” option!

And there’s still real science to be done in the world of meteor shower studies. The International Meteor Organization welcomes counts from volunteers… and be sure to Tweet those Perseid sightings to #Meteorwatch.

Also be sure to check out the UK Meteor Observation Network, which has just launched their live site with streaming images of meteors as they are recorded.

Good luck, clear skies, and let the late 2013 meteor shower season begin!

-And be sure to post those Perseid pics to the Flickr forum on Universe Today… we’ll be doing photo essay roundups from observers around the world!

July 25, 2013December 23, 2015 by Elizabeth Howell

Russian Meteorite Bits Will Be Used In Some 2014 Olympic Medals

Going for gold in the Sochi Winter Olympics could earn athletes some out-of-this-world rocks.

Athletes who top the podium on Feb. 15, 2014 will receive special medals with pieces of the Chelyabinsk meteor that broke up over the remote Russian community on that day in 2013, according to media reports.

“We will hand out our medals to all the athletes who will win gold on that day, because both the meteorite strike and the Olympic Games are the global events,” stated Chelyabinsk Region Culture Minister Alexei Betekhtin in a Ria Novosti report.

The reported sports that will receive these medals include:

Women’s 1,000 meter and men’s 1,500 meter short track;
Men’s skeleton;
Women’s cross-country skiing relay;
Men’s K-125 ski jump;
Men’s 1,500 meter speed skating;
Women’s super giant slalom.

The 55-foot (17-meter) meteor’s airburst in February damaged buildings, causing injuries and fright among those in the region. As astronomers have been collecting fragments and calculating the orbit of the fireball, the incident put renewed attention on the need to monitor space rocks that could threaten the Earth.

Check out this Universe Today collection of videos showing what the meteor looked like.

July 24, 2013December 23, 2015 by David Dickinson

Near-Earth Asteroid 2003 DZ15 to Pass Earth Monday Night

The currnet orbital position of asteroid 2003 DZ15. (Created by the author using JPL's Small-Body Database Browser).

The Earth will get another close shave Monday, when the 152 metre asteroid 2003 DZ15 makes a pass by our fair planet on the night of July 29^th/30^th at 3.5 million kilometres distant. This is over 9 times the Earth-Moon distance and poses no threat to our world.

This is much smaller than 2.75 kilometre 1998 QE2, which sailed by (bad pun intended) our fair world at 5.8 million kilometres distant on May 31st, 2013. The Virtual Telescope Project will be presenting a free online event to monitor the passage of NEA 2003 DZ15 starting Monday night July 29^th at 22:00 UT/6:00 PM EDT.

As of this writing, no efforts are currently known of by professional observatories to monitor its passage via radar, though Arecibo may attempt to ping 2003 DZ15 on Thursday.

An Apollo asteroid, 2003 DZ15 was confirmed by the Lowell Observatory and NEAT’s Mount Palomar telescope upon discovery in February 2003. This is its closest approach to the Earth for this century, although it will make a pass nearly as close to the Earth in 2057 on February 12^th.

With a perihelion (closest approach to the Sun of) 0.63 A.U.s, 2003 DZ15 can also make close passes by the planet Venus as well, which it last did in 1988 and will do again on 2056.

Closest approach of 2003 DZ15 is set for 00:37 UT July 30^th, or 8:37 PM EDT the evening of Monday, July 29^th. Although it will only reach about +14th magnitude (based on an absolute magnitude of +22.2), and hence be out of range to all but the very largest Earthbound backyard telescopes, it’ll be fun to watch as it slowly drifts across the starry background live on the internet. Our own, “is worth tracking down from our own backyard” limit is an asteroid passing closer than our Moon, or is farther, but is brighter than +10^th magnitude… such are the limitations of humid Florida skies!

Of course, an asteroid the size of 2003 DZ15 would spell a bad day for the Earth, were it headed our way. At an estimated 152 metres in size, 2003 DZ is over seven times the size of the Chelyabinsk meteor that exploded over Russia the day after Valentine ’s on February 15^th of this year. While not in the class of an Extinction Level event, 2003 DZ15 would be in 60 to 190 metre size of range of the Tunguska impactor that struck Siberia in 1908.

All enough for us to take notice as 2003 DZ15 whizzes by, at a safe distance this time. NASA plans to launch a crewed mission sometime over the next decade to study an asteroid, and perhaps retrieve a small NEA and place it in orbit about Earth’s Moon. Such efforts may go a long way in understanding and dealing with such potentially hazardous space rocks, when and if the “big one” is discovered heading our way. We’re the Earth’s first line of defense- and unlike the ill-fated dinosaurs, WE’VE got a space program and can do something about it!