Featured Articles – Page 7

Did the Cosmos Deliver a Googly? ‘Meteorite’ Lands on Cricket Pitch

While enjoying a cricket county match, two spectators were apparently treated to one of the rarest of cosmic events: a meteorite falling from the sky, landing right in front of them. The “dark” rock, measuring 5 inches wide, broke in two on impact. Amazingly, a piece hit one of the witnesses.

“One piece bounced up and hit me in the chest and the other ended up against the boundary board,” said Jan Marszel. “It came across at quite a speed – if it had hit me full on it could have been very interesting.”

It’s not clear from the Telegraph‘s minimally skeptical article when this happened (I’m assuming it was during the recent Middlesex vs. Sussex game in Uxbridge, northwest London, using the tidbits of information from the text) and the only expert opinion cited is that of Dr. Matthew Genge, a meteorite expert at Imperial College, who hasn’t handled the evidence yet.

“If this turns out to be a meteorite it’s very exciting and would be the first fall in the UK since 1992,” Genge points out.

(That last statement isn’t very accurate. I’m certain that there have been many meteorites falling onto the UK since 1992. If proven true, this would be the first witnessed fall in the UK since 1992.)

UPDATE (July 27, 10:22 am PT): With thanks to Philip Stobbart, who also commented on the Uxbridge object, some clarification of Genge’s quote has been provided, I stand corrected:

Ian O’Neill does a good job of debunking this, with one minor error. A ‘fall’ to a meteor expert is one of two categories of meteorites, falls and finds, referring to when they were seen – falling, or found later – not to meteorites actually physically falling. The papers made the same error, although they accepted the idea of this being the first fallen meteorite since 1992…

Original post continues:

Thank goodness the eyewitness account didn’t include a description about smoke bellowing from an incendiary-like pebble (i.e. the recent Israel spoof/weapon), but there are some huge question marks hanging over the validity of the Uxbridge object.

The first red flag is that one of the witnesses said: “…out of a blue sky, we saw this small dark object hurtling towards us.” I might be wrong, but spotting a 5-inch wide object flying through the air, at speed, ain’t easy. I would have thought the only time they were alerted of the ‘meteorite’ would have been when it hit the ground. Or when it hit Marszel in the thorax.

Secondly, was the ‘meteorite’ really 5 inches wide? After a quick search, I found a photograph of the offending object:

5 inches? Are you sure? I know us guys are known for overcompensating, but this is ridiculous. Granted, it’s probably just shoddy reporting, but that piece of rock is barely an inch wide.

Also, when a meteoroid blasts through the Earth’s atmosphere, a huge amount of heat is generated around it, creating a ‘fusion crust.’ This crust should be very obvious surrounding recently fallen meteorites. Looking at this picture, no fusion crust is visible. It could be that we are looking at the interior of the broken ‘meteorite,’ and the black fusion crust is on the other side, but there’s no indication in the photo that this is a bona fide space rock.

If I were to place a bet, I’d say that this is not a meteorite. However, it will be interesting to see what the experts think once they are able to study the sample.

Special thanks to Twitter buddy Madge Leebman for the tip!

Strasbourg July Lightning

A bolt of lightning strikes over Strasbourg, France (Ian O'Neill)

As you may have noticed, things have been rather quiet on Astroengine of late. This is partly due to my pan-European trek and my work on Discovery News, but mainly due to my horrid affliction of procrastination. Hence why I’m late in posting this pretty awesome picture of a lightning bolt blasting across the French skies.

What was I doing in France? Well, I was asked to do a lecture all about asteroid mining and space commercialization at this year’s Space Studies Program 2010 (SSP10) at the International Space University (ISU) in Strasbourg earlier this month.

It was an incredible experience and I got to meet some incredible people. Hoping to get a blog post up about the whole thing some time over the coming days, but for now, I’ll leave you with this picture of the storm that hit Strasbourg while I was there. For the full set, check out my Posterous gallery.

Hayabusa Returns to Earth with a Flash

Hayabusa fireball — Hayabusa re-enters over the Australian Outback, generating a bright fireball (screen grabs from the JAXA video feed)

Staring hard at the live streaming video of the black Australian skies, I was hoping to see a faint streak of light glide across the camera’s field of view.

But no, it wasn’t that subtle.

Shortly after 9:51 am EDT on Sunday morning (or, for me, a far more civilized 2:51 pm GMT), the Japanese space agency’s (JAXA) Hayabusa’s mission officially came to an end, burning up in the atmosphere. However, a few hours before, the spacecraft released a 40 cm-wide capsule, sending it ahead of the main spacecraft. This sample return capsule would have a very different re-entry than its mothership.

As I watched the small dot of light on the horizon of the streaming video getting brighter and brighter — feverishly hitting the PRTSC button and using some rapid cut&paste-fu in Photoshop — suddenly it erupted, shedding light on the distant clouds that had been invisible in the night.

Far from the re-entry being a faint or dull event, it was dazzling (as seen in the screen grabs to the right).

So, after seven dramatic years in space, the Hayabusa mission has come to an end.

For the full story about how Hayabusa got hit by the largest solar flare in history, limped to visit an asteroid called Itokawa and how its sample-collecting kit malfunctioned, have a read of my main article on Discovery News: Hayabusa Generates Re-Entry Fireball Over Australia

Note: Thanks to everyone who re-tweeted the sequence of re-entry pics. As of this moment it has received over 30,000 views on Twitpic!

Jupiter Got Smacked, Again

Quite frankly, I’m stunned.

An Australian amateur astronomer has just observed his second ‘once-in-a-lifetime’ event: an impact in the atmosphere of Jupiter. Phil Plait was very quick to get the news out, describing it as a “major coincidence,” and he ain’t wrong!

Anthony Wesley’s first event was the famous July 2009 observation of what was thought to have been the immediate aftermath of a comet impact in the Jovian atmosphere. His second happened on Thursday at 20:31 UTC when he was observing Jupiter when something hit the atmosphere, generating a huge fireball.

It is not known whether this event was caused by a comet or asteroid, but in a bizarre case of serendipity, earlier on Thursday Hubble released more information on his original impact event. The July 2009 “bruise” in the gas giant’s atmosphere is now thought to have been caused by an asteroid, and not a comet.

The Hubble press release included details on how researchers deduced that it was actually more likely that a 500 meter-wide asteroid hit Jupiter in 2009. One clue was that newly installed cameras on the space telescope detected little dust in the halo surrounding the impact site — a characteristic that was detected after the impact of the shards of comet Shoemaker-Levy 9 in July 1994. Also, the calculated trajectory of the 2009 event indicated the object didn’t have an orbit commonly associated with comets. If the 2009 event was an asteroid, that means Wesley saw something never seen before: the site of a recent asteroid impact on a celestial body.

And now, less than a year after being the first to see that impact aftermath, Wesley has done it again. Another amateur astronomer, Christopher Go, was quick to confirm Thursday’s fireball with a video of the 2 second flash in Jupiter’s upper atmosphere.

These impact events serve as a reminder about Jupiter’s fortuitous role in our Solar System. As the gas giant is so massive, its gravitational pull has a huge influence over the outer planets, dwarf planets, comets and asteroids. Acting like an interplanetary ‘vacuum cleaner’ Jupiter can block potentially disastrous chunks of stuff from taking a dive into the inner Solar System. It is thought that this distant planet has helped Earth become the thriving world it is today, preventing many asteroids and comets from ruining our evolution.

Thank you Jupiter!

Awesome.

104078907 — The Moon, Space Shuttle Atlantis, an aurora plus Kibo, all in one breathtaking scene (Soichi Noguchi)

The instant I saw this photograph I realized I was seeing something so beautiful, I’d have a hard job writing something to accompany it.

Coming straight from the Twitter feed of Soichi Noguchi, Japanese astronaut and social-media-in-space-photography-guru, this single photograph has captured the moon, an aurora hanging above the Earth’s limb, a docked space shuttle Atlantis and the International Space Station’s Kibo module (plus a bonus robotic arm and solar panel).

This picture is awesome on so many levels. And to be honest, this should be the photograph of Atlantis’ final mission. It encapsulates so much; a testament to what mankind is capable of and a tribute to the men and women who are currently in space, risking their lives for the advancement of our race.

There’s not much else to say, except: wow.

Black Holes, Aurorae and the Event Horizon Telescope

black-hole-aurora — My impression as to how a black hole 'aurora' might look like near an event horizon (Ian O'Neill/Discovery News)

Usually, aurorae happen when the solar wind blasts the Earth’s atmosphere. However, black holes may also have a shot at producing their very own northern lights. What’s more, we might even be able to observe this light display in the future.

Accretion Disks and Magnetic Fields

Simulating a rapidly spinning black hole, two researchers from Japan modeled an accretion disk spinning with it.

Inside this disk would be superheated plasma and as it rotates it might act like a dynamo, charged particles generating a magnetic field looping through the disk. But this magnetic field wont stay confined to the disk for long. Due to inertial effects, the magnetic field would be dragged into the event horizon, causing the magnetic fieldlines to ‘attach’ themselves to the black hole.

Assuming the accretion disk continues to generate a continuous magnetic field, a global black hole ‘magnetosphere’ would result.

bh-sch — A diagram of the black hole's magnetosphere (Takahashi and Takahashi, 2010)

A Plasma Hosepipe

As you’ve probably seen in the striking imagery coming from the high-definition movies being produced by the Solar Dynamics Observatory, magnetic fieldlines close to the solar surface can fill with solar plasma, creating bright coronal loops. This hot plasma fills the loops, feeding around the magnetic field like a hosepipe filling with water.

The same principal would apply to the black hole’s magnetosphere: the looped magnetic field feeding from the accretion disk to the event horizon filling with plasma as it is sucked out of the disk (by the black hole’s dominating gravitational field).

As you’d expect, the plasma will fall into the black hole at relativistic speeds, converted into pure energy, blasting with intense radiation. However, the Japanese researchers discovered something else that may happen just before the plasma is destroyed by the black hole: it will generate a shock.

As predicted by the model, this shock will form when the plasma exceeds the local Alfven speed. For want of a better analogy, this is like a supersonic jet creating a sonic boom. But in the plasma environment, as the plasma flow hits the shock front, it will rapidly decelerate, dumping energy before continuing to rain down on the event horizon. This energy dump will be converted into heat and radiation.

This fascinating study even goes so far as predicting the configuration of the black hole magnetosphere, indicating that the radiation generated by the shock would form two halos sitting above the north and south ‘poles’ of the black hole. From a distance, these halos would look like aurorae.

Very Large Baseline Interferometry

So there you have it. From a spinning black hole’s accretion disk to shocked plasma, a black hole can have an aurora. The black hole aurora, however, would be generated by shocked plasma, not plasma hitting atmospheric gases (as is the case on Earth).

This all sounds like a fun theoretical idea, but it may also have a practical application in the not-so-distant future.

Last year, I wrote “The Event Horizon Telescope: Are We Close to Imaging a Black Hole?” which investigated the efforts under way in the field of very large baseline interferometry (or “VLBI”) to directly observe the supermassive black hole (Sagittarius A*) living in the center of our galaxy.

In a paper written by Vincent Fish and Sheperd Doeleman at the MIT Haystack Observatory, results from a simulation of several radio telescopes as part of an international VLBI campaign were detailed. The upshot was that the more radio antennae involved in such a campaign, the better the resolution of the observations of the ‘shadow’ of the black hole’s event horizon.

If the black hole’s event horizon could be observed by a VLBI campaign, could its glowing aurorae also be spotted? Possibly.

For more, check out my Discovery News article: “Can a Black Hole Have an ‘Aurora’?” and my Astroengine.com article: “The Event Horizon Telescope: Are We Close to Imaging a Black Hole?“

Was Voyager 2 Hijacked by Aliens? No.

The interstellar probes are still operational (NASA)

The Voyager 2 spacecraft has been speeding through the Solar System since 1977 and it’s seen a lot. Besides scooting past Jupiter, Saturn, Uranus and Neptune, the probe is now passing through the very limit of the heliosphere (called the heliopause) where it has begun to detect a magnetic field beyond the Solar System. The fact we have man-made objects exiting our star system is something that makes me goosebumpily.

For some perspective, Voyager 2 is so far away from Earth that it takes nearly 13 hours for commands sent from Earth to reach the probe.

After decades of travel, the NASA spacecraft continues to relay data back to us, making it one of the most profound and exciting space missions ever launched. Perhaps unsurprisingly, the aging explorer recently experienced a glitch and the data received by NASA was rather garbled.

Naturally, the conspiracy theorists were out in force quickly pointing their sticky fingers at a possible encounter of the 3rd kind. How these ‘aliens’ found the probe in the first place and reprogrammed the transmission for it to appear corrupt Earth-side is beyond me, but according to an ‘expert’ in Germany, aliens (with an aptitude for reprogramming 30 year old Earth hardware, presumably) were obviously to blame.

One of the alien implication articles came from yet another classic ‘science’ post thrown together by the UK’s Telegraph where they decided to take the word of a UFO expert (obviously a viable source) without any kind of counter-argument from a real expert of real science. (But this is the same publication that brought us other classics such as the skull on Mars and the Doomsday Turkey, so it’s not too surprising.)

As I discussed in a recent CRI English radio debate with Beyond Beijing hosts Chris Gelken and Xu Qinduo, the Voyager-alien implication is beyond funny; an entertaining sideline to poke fun at while NASA worked out what actually went wrong. But the big difference was that Chris and Xu had invited Seth Shostak (from the SETI Institute) and Douglas C. Lin (from the Kavli Institute for Astronomy and Astrophysics at Peking University) to join the fun. No UFO expert in sight, so the discussion was biased toward science and logic, not crazy talk.

(It was an awesome show by the way, and you can check out the recording via my Discovery News article.)

So what did happen to Voyager 2? It turns out that aliens are not required to answer this cosmic mystery.

On Tuesday, NASA announced that Voyager 2 had flipped one of its bits of memory the wrong way. “A value in a single memory location was changed from a 0 to a 1,” said JPL’s Veronia McGregor.

This glitch was thought to occur in the flight data system, which formats information for transmission to Earth. Should something go wonky in its memory allocation, the stuff it transmits can be turned into gibberish.

Although it isn’t known how this single bit was flipped (and we may never know, as Voyager 2 is an awful long way from home), it sounds very much like a cosmic ray event interfering with the onboard electronics. As cosmic rays are highly energetic charged particles, they can penetrate deep into computer systems, causing an error in calculations.

And this situation isn’t without precedent either. Recently, NASA’s Mars Reconnaissance Orbiter (MRO) was hit by a cosmic ray event, causing the onboard computer to switch to “safe mode.” Also, Voyager 2 is beginning to exit the Sun’s outermost sphere of influence, where turbulence and confused magnetic fields rule. If I had to guess, I’d say — statistically-speaking — the probe might have a greater chance of being hit by the most energetic cosmic rays from deep space.

Just because something “mysterious” happens in space doesn’t mean aliens, the Illuminati or some half-baked doomsday phenomenon caused it. Before jumping to conclusions it would be nice if certain newspapers and UFO experts alike could look at the most likely explanation before pulling the alien card.

Alas, I suspect that some things will never change.

Life on Mars? Only in The Sun.

In its haste to become the first newspaper to print the “NASA: Evidence of Life on Mars” headline, the UK’s Sun website caused a stir last week. Not only was this headline incorrect, it was a wee bit irresponsible.

For starters, no evidence for life has been found on the Red Planet. Second, NASA has not proclaimed such a discovery. In fact, The Sun riled the U.S. space agency so much, this headline prompted NASA spokesman Dwayne Brown to issue the following statement:

“This headline is extremely misleading. This makes it sound like we announced that we found life on Mars, and that is absolutely, positively false.”

So where did it all go so wrong?

This story stems from an astrobiology conference celebrating the 50th anniversary of the search for alien life. At this conference, findings by NASA’s Mars Exploration Rover Opportunity were reviewed. One of these findings was the tantalizing discovery of sulfates by the rover in 2004. Where there’s sulfates, water once existed. Where there’s water, life might have existed.

In an exciting twist to this discovery, scientists studying sulfate deposits on Earth (known as gypsum) were asked by scientists in the Mars Program to investigate terrestrial gypsum deposits more closely. Up until now, it was thought that gypsum contained no fossils, but on closer inspection it turns out that ancient gypsum deposits from the Mediterranean Sea (dated to about 6 million years old — when the sea was actually dry) are stuffed full of microscopic fossils of algae and phytoplanktons.

So, on Mars we have sulfates. On Earth we have sulfates (gypsum) full of fossils of aquatic microscopic life. If we know the terrestrial deposits of gypsum contain fossils of basic life forms, perhaps sulfate deposits on Mars would be a good place to start looking for basic ancient extraterrestrial life.

Of course, for the tabloid newspaper, these Martian sulfate deposits became “pond scum” and therefore “evidence” for life on Mars.

In actuality, the text of The Sun article wasn’t that misleading and actually did a good job of reporting the science (apart from the “pond scum” bit). Unfortunately, the title of the article let the rest of the article down, ultimately undermining the journalists’ work.

But, coming from the same publication that printed the silly “Pictures show life on Mars” article from 2008, the “Evidence for life on Mars” headline is pretty tame.

Now, time for the same news with a more appropriate headline by Irene Klotz on Discovery News: “Earth Fossil Find May Lead to Martian Discoveries”

Thanks to Astroengine.com reader Judy Mason for inspiring this post.

Gecksteroids! Asteroids and Geckos May Share Common Force

The asteroid Itokawa (as imaged by the Japanese Hayabusa probe) and a gecko tattoo. Bear with me, it'll make sense soon (JAXA)

What do asteroids and geckos have in common? Not a lot, as you’d expect, but they may share a common force.

This rather strange notion comes from research being done by a team of University of Colorado scientists who have been studying the odd nature of the asteroid Itokawa. When the Japanese Hayabusa mission visited the space rock in 2005 (Hayabusa’s sample return capsule is set to return to Earth on June 13th by the way), it noticed the asteroid was composed of smaller bits of rubble, rather than one solid chunk. Although this isn’t a surprise in itself — indeed, many asteroids are believed to be floating “rubble piles” — the rate of spin of the asteroid posed a problem.

Itokawa spins rather fast and if only the force of gravity was keeping the lumps of rock together, they would have been flung out into space long ago. In short, the asteroid shouldn’t exist.

Although plenty of theories have been bandied around, one idea seems to stick.

More commonly found as a force that holds molecules together, the van der Waals force may bind the individual components of the asteroid together, acting against the centripetal force caused by its spin.

But where do the geckos come in?

Geckos are highly skilled in the “climbing up walls” department, and it’s the van der Waals force that makes this happen. Should the body of a gecko be tilted in such a way against a perfectly smooth, “impossible” to climb surface, the gravity acting on the little creature will trigger the force into action. Therefore geckos have evolved to exploit the practical application of van der Waals.

This has some rather interesting ramifications for asteroid evolution too. During early stages of asteroid formation, the larger fragments of rock are flung off; the centripetal force exceeds that of gravity. In the latter stages of development, only the smallest rocks remain behind, their mass small enough to allow van der Waals forces to overcome the spin.

So, there you have it, asteroids do have something in common with geckos. It seems only right to call these space rubble piles “Gecksteroids.”

Thanks to my Discovery News colleague Jennifer Ouellette for drawing the comparison between asteroids and geckos!

Source: Discovery News, arXiv.org

Indonesia ‘Meteorite’ Wiped Out a House… Or Not.

A week after Israel played host to the amazing burning ‘meteorite’, another report is coming in about a ‘meteorite’ strike in East Jakarta, Indonesia. (Note the use of the famous ‘skeptical quotes’.)

On Thursday, a falling object crashed through the roof of a house causing moderate damage. There was also light damage to two adjoining properties. Fortunately, there are no reported injuries.

According to a report in the Jakarta Globe, there was a “blast” that resulted from the impact and there was a deep crater in the floor of the house. After creating the impact crater in the floor, the ‘falling object’ bounced.

“I suspect the object impacted at high velocity, hit the floor, bounced back and hit the ceiling, then fell back down,” said a researcher from the Indonesian National Aeronautics and Space Agency (Lapan). “It’s extremely difficult to recover the fragments, what with the rubble and broken glass, and it being so dark in here.”

The article also states that there was evidence for a residual heat footprint and melted items around the crater. Apparently, these facts all point to evidence that a meteorite, or some man-made space junk, was involved.

Although the details are sketchy, there are a few points that concern me about this meteorite report:

First, if this ‘meteorite’ was large enough to create a “deep” crater (there’s no information about the crater’s approximate size), that would suggest it was a hyper-velocity impact. Not only is this kind of impact very rare, I doubt there would be anything left of the building.

Unless “moderate damage” means “there is no house left,” I strongly doubt the crater was caused by a meteorite.

Secondly, according to the Lapan scientist, the space rock “bounced.” While this is possible — take the Virginia meteorite that crashed through the roof of a doctors office, bouncing off the floor of an examination room, for example — if its impact was energetic enough to excavate a sizable crater (and produce a “blast”), then I doubt much of the meteorite would be left to “bounce.” It would have disintegrated, got lodged deep in the bottom of the crater, or not produced a crater at all.

Thirdly, the article states: “the residual heat footprint and melted items pointed to a meteorite.” As I’ve said before, meteorites are usually cold when they make landfall (assuming they are small enough to be slowed by our atmosphere), so this residual heat did not come from the meteorite. If the meteorite was large enough to slam into the house at hyper-velocity speeds, or hit a gas canister, then perhaps there might be some “residual heat.” But in this case, I strongly doubt there would be any house left.

Fourthly, according to Evan Irawan Akbar, from the Bosscha Observatory in Lembang, this event has occurred shortly after the Lyrid meteor shower which ended on Monday. So he rules out any connection. Which is fortunate, as this meteor shower is caused by the Earth passing through a harmless dust tail created by the periodic Comet C/1861 G1 Thatcher.

But then he drops this clanger: “It could, however, be part of the Eta Aquariid meteor shower, which peaks on May 7 and 8.”

The Eta Aquariid meteor shower is caused by dust trail from Halley’s Comet… last time I checked, dust grains from comets have never been linked with house-killing chunks of rock. Comets are made from ice and dust, stuff that easily burns up when hitting our atmosphere. These are meteor showers, not meteorite showers.

The extent of the damaged caused is also a little strange. From the article: “It blasted a hole in the second floor of the house, sending furniture falling to the first floor, and tore big holes in the walls.” Doesn’t that sound like an explosion?

Apparently the police have ruled out speculation that this was a gas canister explosion and although there is “no conclusive proof the damage was caused by a meteorite, it was the most likely explanation.”

Alas, meteorite impacts aren’t likely explanations, terrestrial explanations are the most “likely.” The fact that an Indonesian counter-terrorism squad has been dispatched to the area to look for traces of explosives suggest the authorities aren’t placing all their bets on this being a meteorite impact either.

Thanks to @antonwilliam for the tip!

Source: Jakarta Globe