Another Reminder, Go See the Perseids


My favourite meteor show is less than 2 weeks away now, so I wanted to give you all another gentle reminder to get organized and make sure that you’re able to enjoy the Perseid meteors this year – the shower will be peaking on the night of August 12, and into the next morning. It’s going to be a special event because the shower coincides with a new moon. The sky will be at its darkest, and the meteors will be at their brightest.

The shower gets its name because they will appear to originate from the constellation of Perseus. Don’t worry about finding the constellation, though, just lay on your back and stare up, you’ll see them.

On the evening of August 12, the first thing you’ll want to do is head outside shortly after sunset. If you’re lucky, you’ll see “earthgrazers”. These are some of the most beautiful meteors that you’ll see in the whole evening. Then settle down, find some satellites, and wait for the show to really get going. It you’ve got the stamina, the best viewing will happen in the early dawn hours of Monday, August 13th. At that point, you could be seeing a few dozen every hour.

To really get the best experience out of this, travel away from the lights of the city. Here in Vancouver, we need to get about 50 km away to start seeing the Milky Way above our heads. We’ve got a dark sky park in a suburb called Abbotsford that’s perfect.

So get organized. Book the evening with your friends, map out where you’re going to go. Bring hot drinks, warm clothes, and a comfortable place to sit back and enjoy the show.

And if you’re interested, Pamela and I recorded an episode of Astronomy Cast dealing with meteors and meteor showers, so you can listen in the car before you reach your viewing spot.

Enjoy, and let me know how it goes.

Set Your Calendar for the 2007 Perseids: August 12th


My absolute favourite meteor shower every year is the Perseids. They’re not the most spectacular meteors of the year, but the weather’s nice and warm here in Canada. We always head back home to Hornby Island to visit the family at Perseid time to enjoy them with nice dark skies. We keep the kids awake as long as possible, and then lay back on a mattress, enjoying the sky show.

And this year’s going to be a great one: no moon.

That’s right, there’s going to be a new moon on Sunday, August 12th, the exact same time that the Perseid shower is peaking. Without the glare of the Moon, the meteors will be at their brightest. But to really enjoy the show, you’ll want to head outside your city, away from the glare.

Like all meteor showers, the Perseids get their name from the constellation the meteors originate from. The constellation is in the northeast. As soon as it starts to get dark, you should start seeing meteors streaking across overhead. It’ll probably just be a couple every minute, but by early morning, when the shower is peaking, you could even see a few dozen a minute.

And as a special bonus, Mars is going to be in the sky as well. It’ll appear to be a bright red star also in the northeast.

I want you to organize something for the Perseids this year. Gather together some great friends, head somewhere dark, and plan to enjoy a great show. Put it on your calendar right now.


Original Source: NASA

Watch for the Geminids on Wednesday

Credit: Jason A.C. BrockOne of the best meteor showers of the year – the Geminids – are about to peak. If you’ve got clear skies, head out on the evening of December 13th, and you could see a few meteors an hour. Unlike most meteor showers, the source of the Geminids is a bit of a mystery, since the dust doesn’t seem to originate from a comet. A small asteroid called 3200 Phaethon has been discovered in the right orbit, but astronomers aren’t sure how it could be generating enough dust to cause such beautiful meteor showers.
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Organic Material Found in an Ancient Meteorite

NASA researchers have discovered organic material inside a meteorite the recently fell in Canada’s Tagish Lake. The meteorite is especially valuable because scientists collected it shortly after it crashed in 2000, ensuring it wasn’t contaminated by local bacteria. The meteorite seems to contain many small hollow organic globules, which probably formed in the cold molecular cloud of gas and dust that gave birth to the Solar System. Meteorites like this have been falling to Earth for billions of years, and probably seeded the early planet with organic material.
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Leonid Meteor Shower: November 19, 2006

One of the best meteor showers of the year is about to get rolling, so make sure you mark your calendar. The Leonid Meteor Shower will be peaking on Sunday, November 19, 2006, and you might be able to see as many as 100 meteors an hour. Find the darkest possible skies that you can, and wait until the constellation Leo is highest in the sky. Observers in western Europe, Africa, Brazil and the eastern parts of North America will get the best view this year.
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The Link Between Asteroids and Meteorites

In theory, asteroids and meteorites are made of the same basic elements; it’s just that asteroids are much much bigger. But scientists had always found troubling chemical differences between the two kinds of objects. New data gathered by the Japanese spacecraft Hayabusa, which recently visited the near-Earth asteroid Itokawa, shows that there’s a good reason for the difference. It’s the long-term effect of space weathering – solar and cosmic radiation – that changes the surface of asteroids to look different from meteorites.
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Washed Out Perseids Will Peak on Friday

One of the best meteor showers of the year – the Perseids – will get washed out by a nearly full Moon this year. But that doesn’t mean you shouldn’t try and enjoy them anyway. The Moon will be 87% full on Friday, August 11, rising after 10:00pm. Head out after it goes dark, and see if you can spot an Earth grazer; a special kind of meteor that can be very bright and slow, leaving a dramatic tail. After 10:00pm, only the brightest meteors will be visible. 2007 will be much better, when it’ll be a moonless sky.
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Meteoroid Strike on the Moon

NASA researchers fortunate enough to be recording the Moon through a 10″ telescope equipped with a video camera when they saw a meteoroid strike. The spacerock was only 25 cm (10 inches) wide, but it released 17 billion joules of kinetic energy; the same as 4 tons of TNT. The resulting flash was quick, only lasting 4/10ths of a second, but it was powerful enough to carve out a crater 14 metres (46 feet) wide.
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New Technique for Finding Organic Molecules in Meteorites

Tiny particles of meteorites with portions of nitrogen and hydrogen. Image credit: Henner Busemann. Click to enlarge
When the Solar System first formed billions of years ago, organic molecules – the building blocks of life – were churned into the mix that went on to create the planets. Scientists from the Carnegie Institution have developed a technique to find these tiny organic particles hidden inside meteorites. These meteorites have survived since the formation of the Solar System, so it allows scientists to track the distribution of organic material and the processes they went through as the planets formed.

Like an interplanetary spaceship carrying passengers, meteorites have long been suspected of ferrying relatively young ingredients of life to our planet. Using new techniques, scientists at the Carnegie Institution’s Department of Terrestrial Magnetism have discovered that meteorites can carry other, much older passengers as well-primitive, organic particles that originated billions of years ago either in interstellar space, or in the outer reaches of the solar system as it was beginning to coalesce from gas and dust. The study shows that the parent bodies of meteorites-the large objects from the asteroid belt-contain primitive organic matter similar to that found in interplanetary dust particles that might come from comets. The finding provides clues about how organic matter was distributed and processed in the solar system during this long-gone era. The work is published in the May 5, 2006, issue of Science.

“Atoms of different elements come in different forms, or isotopes, and the relative proportions of these depend on the environmental conditions in which their carriers formed, such as the heat encountered, chemical reactions with other elements, and so forth,” explained lead author Henner Busemann. “In this study we looked at the relative amounts of different isotopes of hydrogen (H) and nitrogen (N) associated with tiny particles of insoluble organic matter to determine the processes that produced the most pristine type of meteorites known. The insoluble material is very hard to break down chemically and survives even very harsh acid treatments.”

The researchers used a microscopic imaging technique to analyze the isotopic composition of insoluble organic matter from six carbonaceous chondrite meteorites-the oldest type known. The relative proportion of isotopes of nitrogen and hydrogen associated with the insoluble organic matter act as “fingerprints” and can reveal how and when the carbon was formed. The isotope of nitrogen that is most often found in nature is 14N; its heavier sibling is 15N. Differing amounts of 15N, in addition to a heavier form of hydrogen called deuterium, (D), allow researchers to tell if a particle is relatively unaltered from the time when the solar system was first forming.

“The tell-tale signs are lots of deuterium and 15N chemically bonded to carbon,” commented co-author Larry Nittler. “We have known for some time, for instance, that interplanetary dust particles (IDP), collected from high-flying airplanes in the upper atmosphere, contain huge excesses of these isotopes, probably indicating vestiges of organic material that formed in the interstellar medium. The IDPs have other characteristics indicating that they originated on bodies-perhaps comets-that have undergone less severe processing than the asteroids from which meteorites originate.”

The scientists found that some meteorite samples, when examined at the same tiny scales as interplanetary dust particles, actually have similar or even higher abundances of 15N and D than those reported for IDPs. “It’s amazing that pristine organic molecules associated with these isotopes were able to survive the harsh and tumultuous conditions present in the inner solar system when the meteorites that contain them came together,” reflected co-author Conel Alexander. “It means that the parent bodies-the comets and asteroids-of these seemingly different types of extraterrestrial material are more similar in origin than previously believed.”

“Before, we could only explore minute samples from IDPs. Our discovery now allows us to extract large amounts of this material from meteorites, which are large and contain several percent of carbon, instead of from IDPs, which are on the order of a million million times less massive. This advancement has opened up an entirely new window on studying this elusive period of time,” concluded Busemann.

Original Source: Carnegie Institution

Microscopic Tunnels Carved by Martian Microbes?

A thin slice of the Nakhla meteor. Image credit: OSU Click to enlarge.
Bacteria seem to live anywhere there’s water. One class of bacteria are known to burrow through igneous rock feeding on iron and other chemicals, and leaving a tiny tunnel behind them. Now researchers have found similar tunnels in a meteorite believed to have originated on Mars called the Nakhla meteorite. This adds additional data to the mounting evidence that Mars was wet in the distant past, and gives the tantalizing possibility that it was inhabited with life.

A new study of a meteorite that originated from Mars has revealed a series of microscopic tunnels that are similar in size, shape and distribution to tracks left on Earth rocks by feeding bacteria.

And though researchers were unable to extract DNA from the Martian rocks, the finding nonetheless adds intrigue to the search for life beyond Earth.

Results of the study were published in the latest edition of the journal Astrobiology.

Martin Fisk, a professor of marine geology in the College of Oceanic and Atmospheric Sciences at Oregon State University and lead author of the study, said the discovery of the tiny burrows do not confirm that there is life on Mars, nor does the lack of DNA from the meteorite discount the possibility.

“Virtually all of the tunnel marks on Earth rocks that we have examined were the result of bacterial invasion,” Fisk said. “In every instance, we’ve been able to extract DNA from these Earth rocks, but we have not yet been able to do that with the Martian samples.

“There are two possible explanations,” he added. “One is that there is an abiotic way to create those tunnels in rock on Earth, and we just haven’t found it yet. The second possibility is that the tunnels on Martian rocks are indeed biological in nature, but the conditions are such on Mars that the DNA was not preserved.”

More than 30 meteorites that originated on Mars have been identified. These rocks from Mars have a unique chemical signature based on the gases trapped within. These rocks were “blasted off” the planet when Mars was struck by asteroids or comets and eventually these Martian meteorites crossed Earth’s orbit and plummeted to the ground.

One of these is Nakhla, which landed in Egypt in 1911, and provided the source material for Fisk’s study. Scientists have dated the igneous rock fragment from Nakhla – which weighs about 20 pounds – at 1.3 billion years in age. They believe that the rock was exposed to water about 600 million years ago, based on the age of clay found inside the rocks.

“It is commonly believed that water is a necessary ingredient for life,” Fisk said, “so if bacteria laid down the tunnels in the rock when the rock was wet, they may have died 600 million years ago. That may explain why we can’t find DNA – it is an organic compound that can break down.”

Other authors on the paper include Olivia Mason, an OSU graduate student; Radu Popa, of Portland State University; Michael Storrie-Lombardi, of the Kinohi Institute in Pasadena, Calif.; and Edward Vicenci, from the Smithsonian Institution.

Fisk and his colleagues have spent much of the past 15 years studying microbes that can break down igneous rock and live in the obsidian-like volcanic glass. They first identified the bacteria through their signature tunnels then were able to extract DNA from the rock samples – which have been found in such diverse environments on Earth as below the ocean floor, in deserts and on dry mountaintops.

They even found bacteria 4,000 feet below the surface in Hawaii that they reached by drilling through solid rock.

In all of these Earth rock samples that contain tunnels, the biological activity began at a fracture in the rock or the edge of a mineral where the water was present. Igneous rocks are initially sterile because they erupt at temperatures exceeding 1,000 degrees C. – and life cannot establish itself until the rocks cool. Bacteria may be introduced into the rock via dust or water, Fisk pointed out.

“Several types of bacteria are capable of using the chemical energy of rocks as a food source,” he said. “One group of bacteria in particular is capable of getting all of its energy from chemicals alone, and one of the elements they use is iron – which typically comprises 5 to 10 percent of volcanic rock.”

Another group of OSU researchers, led by microbiologist Stephen Giovannoni, has collected rocks from the deep ocean and begun developing cultures to see if they can replicate the rock-eating bacteria. Similar environments usually produce similar strains of bacteria, Fisk said, with variable factors including temperature, pH levels, salt levels, and the presence of oxygen.

The igneous rocks from Mars are similar to many of those found on Earth, and virtually identical to those found in a handful of environments, including a volcanic field found in Canada.

One question the OSU researchers hope to answer is whether the bacteria begin devouring the rock as soon as they are introduced. Such a discovery would help them estimate when water – and possibly life – may have been introduced on Mars.

Original Source: OSU News Release