First verified meteorite death ever? No, and here's why not
Wednesday, February 10, 2016, 11:47 AM - According to news reports from India, a man in the southern state of Tamil Nadu was thought to be the first death by meteorite strike in recorded history. Do the details really add up, though? No. Here's why not.
On Saturday, February 6, at roughly 12:30 p.m. local time, an explosion rocked the campus of Bharathidasan Engineering College, located in the town of Natrampalli, India.
The blast shattered windows in surrounding buildings, cracked windshields of nearby vehicles and destroyed a water tank, leaving a 2-metre wide crater in the ground. According to reports, a college employee by the name of Kamaraj was killed, while at least three others were injured in the blast.
Investigating into the cause of the explosion, police came to a somewhat unusual conclusion.
"We can rule out the possibility of any terror angle or sabotage. Not a single ingredient pertaining to any kind of explosive was found at the site. We suspect it to be a meteorite fall," a top police official said, according to The Hindu.
If this actually turns out to be the case, it would represent the first verified human death from a meteorite strike in recorded history. According to records maintained by Harvard University's International Comet Quarterly, the last plausible death attributed to a meteorite was on January 16, 1825, when a man in India was struck and killed, however the account has only been listed as "possible."
Digging in the crater, the police reportedly pulled out a small, dark stone, with mass of about 10 grams, which was described as being black, irregularly shaped, and appearing like "eeyam" (which translates as "lead"). While that could describe an iron meteorite, there are several inconsistencies in the story that call that particular conclusion into question.
The details just don't add up
According to Dr. Peter Brown, a professor of physics at Western University, in London, who is an expert on meteors, meteoroids and meteorites, the very first part of the account - the explosion itself - makes it very unlikely that this was caused by a meteorite.
In an email to The Weather Network, Professor Brown said that a meteorite impact that could actually produce an explosion would have left a crater at least 10 metres in diameter.
Smaller craters can be produced by meteorite impacts, however they would not be explosive - that is, powerful enough to produce a shock wave that could cause the kind of collateral damage reported in Saturday's incident. Why? Because these objects, even the densest of them, are just not travelling fast enough when they reach the ground.
When they first plunge into the upper atmosphere, meteoroids are travelling at speeds in the tens of thousands of kilometres per hour, at the very least. They compress the air in their path into a glowing plasma, and slow down as the air pressure pushes back against them. When they shed enough of their initial speed, they can't compress the air enough to make it glow. The light winks out and they enter the "dark flight" phase of their journey. They simply become rocks falling under the influence of gravity, and are travelling at speeds of up to 300 km/h by the time they hit the ground. That's less than one-tenth of the speed of a bullet from a modern rifle, and certainly not fast enough for a 10-gram rock to produce a 2 metre crater and an explosion intense enough to shatter windows and kill a man.
So, just from the reports of the explosion, the chances of this being meteoric in origin are fairly low, if not zero.
Prof. Brown also noted the lack of a "bolide" in this case.
At the speeds that meteoroids enter the atmosphere, they invariably cause a bright meteor in the sky.
For an object capable of striking the ground with such force as to leave a 2-metre wide crater, it would have produced what astronomers call a bolide - a meteor fireball that shines at least as bright as the full moon. Bolides seen in the past have lit up night skies as bright as daytime, and are so bright that they are typically noticeable even during the day.
The most dramatic example of this in recent times was on February 15, 2013. Characterized as a "super bolide," a meteoroid weighing in at over 10,000 metric tonnes flew over the southern Ural region of Russia before exploding in an air burst over the city of Chelyabinsk. The shock wave from the air burst damaged buildings, broke glass and resulted in nearly 1,500 injuries.
The fact that no flash of light was seen on the campus is not particularly unusual, even if this were a meteorite strike. This is because even large meteoroids tend to "burn out" quite high up. The Chelyabinsk meteoroid produced a bright bolide starting at around 90-100 km above the ground, and it finally winked out at around 15 km up. So, from well above the cruising altitude of a jetliner, the fragments from this meteoroid fell to the ground without producing any light in the process (which is why it took authorities some time to find the main pieces).
Therefore, if this was a meteorite, the bolide it produced would not have necessarily been seen from the college campus. Even so, the northern part of the state of Tamil Nadu is a fairly densely populated area, and Vellore district is within 150 kilometres of both Chennai and Bengaluru - major cities with populations of more than 4 million people each. A bolide would have been visible across the region, and eyewitness reports would have already come pouring in.
NASA weighs in
Late in the day on Tuesday, NASA released a statement regarding the incident, confirming the same details that Professor Brown had discussed with The Weather Network on Monday.
"Initial assessment based on photos posted online are not consistent with something from space," NASA spokesman Dwayne Brown said, according to ABC News. "Small meteorites do not start fires or cause explosions when they hit the ground. To form a crater the size of what has been posted online would have required a meteorite of at least several kilograms. While more details are forthcoming from local scientists, this is unlikely something from space."
Scientists at the Indian Institute of Astrophysics (IIA), Bengaluru, are reportedly examining the stone recovered from the crater. It remains to be seen what they will find, but based on the evidence presented so far, the chances of them reporting that it is actually a meteorite are fairly low.
DID YOU SEE IT? Bright meteor fireball, as seen from Falls Church, VA, Saturday, January 30, 2016