Tunguska “Trench” Found

The Tunguska asteroid of 1908, discussed here, is often referred to as an “event” of unspecified origin because no crater had been identified.   Now, it appears, one has been found. 

In their new study, a team of Italian scientists used acoustic imagery to investigate the bottom of Lake Cheko, about five miles (eight kilometers) north of the explosion’s suspected epicenter.

“When our expedition [was at] Tunguska, we didn’t have a clue that Lake Cheko might fill a crater,” said Luca Gasperini, a geologist with the Marine Science Institute in Bologna who led the study.

“We searched its bottom looking for extraterrestrial particles trapped in the mud. We mapped the basin and took samples. As we examined the data, we couldn’t believe what they were suggesting.

“The funnel-like shape of the basin and samples from its sedimentary deposits suggest that the lake fills an impact crater,” Gasperini said.

The crater is not round, but elongated, like a trench.  The mental picture I get is of a wheel-shaped chunk, spinning and rolling and then diving into the muddy ground.

If the chunk survived the explosion long enough to create a trench, wouldn’t that mean it’s still down there somewhere?  

A Few Updates

Time to catch breath. I've blogged on far more topics than I expected to when I started this up. I have received so many kind comments, both on- and off-line. I intend to continue it indefinitely, because I love writing it.

Some of the things I've blogged about deserve another quick look:

Salute to Ray Davies was prompted by the upcoming release of the longtime Kinks' leader's first solo album. I expressed nervousness about whether the CD would be good. The late Kinks albums were pretty weak.

Well, the album, "Other People's Lives" is out and it's not merely good, it's great from beginning to end. It manages to capture everything fans love about Ray, and yet sound quite different from anything he's done before. That might be because, as he explains in the liner notes, his Kinks songs were written in the studio, which suggests they were written to order, on deadline, with an expensive clock running, perhaps a little slapdash. This time, Davies labored his songs. He risked overthinking, but the extra effort pays off. I can't tell you what my favorite song is yet. There might be a "Waterloo Sunset"-level masterpiece among them.

Some will miss that shambling Kinks style. Ray's brother Dave was a guitarist of little technique and a lot of attitude. The skilled session musicians on the new one, aided by digital recording technology, come up with a much different sound — more rhythmic, more soulful, more American. Davies' vocals are strong and, as in his best Kinks music, very human. "Other People's Lives" is not to be missed.

I asked "Will There Be Flowers?" in Borrego Springs this March. I didn't make it out there, but apparently there is only a limited bloom due to the late-arriving rainfall. Things are a little more colorful in Death Valley. North of Los Angeles, the California Poppy Reserve is flourishing, and probably worth a trip. Check this site for desert wildflowers sightings throughout the desert southwest.

Hee Seop Choi is on the Red Sox's disabled list. His Dodger replacement, Nomar Garciaparra, looks like he's heading there, too, along with another new Dodger Codger, Kenny Lofton. To paraphrase Earl Weaver, Ned Colletti just got a lot dumber, and a lot closer to his injury snake-bit predecessor, Paul DePodesta.

The Tunguska meteor theory of global warming hasn't picked up much traction, although one of my commenters endorsed it. I'm not sure if I even endorse it! But I like asking questions.

Nobody's bought the former Knight-Ridder newspapers that McClatchy put up for sale, but bids are coming in, including a combined bid from the Newspaper Guild and Ron Burkle's L.A.-based Yucaipa investment firm.

Blogging turns out to be a good way to connect with old friends and forgotten enthusiasms. I wrote about the history of Elliot Mintz, spokesman for Paris Hilton and, before that, John Lennon, and got lots of great memories of 60s and 70s radio lore in the comments area. This blog has put my family and me back in touch with several long-lost friends — what could be more gratifying? People my age are starting to finally live their dreams, to rethink their careers, and to cherish the good health of their loved ones. It's also been wonderful to hear from other bloggers whose work I greatly respect, and from my fellow denizens of the greatest site on the whole Internet, Dodger Thoughts. Your kind words about this site mean so much to me.

Back in December, I started this blog with a somewhat dramatic, breathless recounting of the last three weeks of my last job — including a ferry ride across an icy lake that struck me as symbolic of my situation. In that post, I mentioned that, shortly after I lost that job, I was indicted. Now, 15 months later, I finally get my trial, starting tomorrow.

I've gotten so many wonderful notes of support and good wishes, and I'm so grateful for them. Many of these notes say something to the effect of, "You must be so stressed out." Well, the adrenaline is certainly pumping; I'm highly alert. But, no, I'm not stressed out. I'm a fortunate person. I have an amazing wife, a wonderful son, a brilliant and supportive family, and so many great friends. And, I believe our justice system ultimately will be fair.

During the trial, which will last about four weeks, blogging here will be light. There might be a guest comment or two. I'm not going to use this site to address my case while it is going on. If I do post, it will be the usual stuff I write about. Whatever that is.

Blame it on the Asteroid

Another good post on Science Blog, which I just stumbled across today: A report on a controversial new theory to account for global warming.

On June 30, 1908, there was a cataclysmic event in Siberia that is still not completely understood. According to one eyewitness, a Shanyagir tribesman:

We had a hut by the river with my brother Chekaren. We were sleeping. Suddenly we both woke up at the same time. Somebody shoved us. We heard whistling and felt strong wind. Chekaren said, “can you hear all those birds flying overhead?” We were both in the hut, couldn’t see what was going on outside. Suddenly, I got shoved again, this time so hard I fell into the fire. I got scared. Chekaren got scared too. We started crying out for father, mother, brother, but no one answered. There was noise beyond the hut, we could hear trees falling down. Me and Chekaren got out of our sleeping bags and wanted to run out, but then the thunder struck. This was the first thunder. The Earth began to move and rock, wind hit our hut and knocked it over. My body was pushed down by sticks, but my head was in the clear. Then I saw a wonder: trees were falling, the branches were on fire, it became mighty bright, how can I say this, as if there was a second sun, my eyes were hurting, I even closed them. It was like what the Russians call lightning. And immediately there was a loud thunderclap. This was the second thunder. The morning was sunny, there were no clouds, our Sun was shining brightly as usual, and suddenly there came a second one!

Me and Chekaren had some difficulty getting under from the remains of our hut. Then we saw that above, but in a different place, there was another flash, and loud thunder came. This was the third thunder strike. Wind came again, knocked us off our feet, struck against the fallen trees.

We looked at the fallen trees, watched the tree tops get snapped off, watched the fires. Suddenly Chekaren yelled “Look up” and pointed with his hand. I looked there and saw another flash, and it made another thunder. But the noise was less than before. This was the fourth strike, like normal thunder.

Now I remember well there was also one more thunder strike, but it was small, and somewhere far away, where the Sun goes to sleep.

This was the “Tunguska event.” The scientific near-consensus is that it was caused by the airburst from a meteorite, comet or asteroid hurtling toward Earth, exploding 6-10 kilometers above the surface. It destroyed, among other things, 60 million trees. But it left no crater, which indicates the object exploded into flaming dust before impact, releasing 10-15 megatons of energy into the air. The skies above Europe glowed at night for several evenings afterward — bright enough to read by.

Vladimir Shaidurov from the Russian Academy of Science now believes this cosmic event might be responsible for the pronounced climate change that began early in the 20th Century– global warming.  According to Shaidurov’s theory, “changes in the amount of ice crystals at high altitude could damage the layer of thin, high altitude clouds found in the mesosphere that reduce the amount of warming solar radiation reaching the earth’s surface.” This effect could be the result of the Tunguska event. From Science Blog’s post:

(T)he most potent greenhouse gas is water, explains Shaidurov and it is this compound on which his study focuses. According to Shaidurov, only small changes in the atmospheric levels of water, in the form of vapour and ice crystals can contribute to significant changes to the temperature of the earth’s surface, which far outweighs the effects of carbon dioxide and other gases released by human activities. Just a rise of 1% of water vapour could raise the global average temperature of Earth’s surface more then 4 degrees Celsius.

(snip)

Water vapour levels are even less within our control than CO2 levels. According to Andrew E. Dessler of the Texas A & M University writing in ‘The Science and Politics of Global Climate Change’, “Human activities do not control all greenhouse gases, however. The most powerful greenhouse gas in the atmosphere is water vapour, he says, “Human activities have little direct control over its atmospheric abundance, which is controlled instead by the worldwide balance between evaporation from the oceans and precipitation.”

As such, Shaidurov has concluded that only an enormous natural phenomenon, such as an asteroid or comet impact or airburst, could seriously disturb atmospheric water levels, destroying persistent so-called ‘silver’, or noctilucent, clouds composed of ice crystals in the high altitude mesosphere (50 to 85km). The Tunguska Event was just such an event, and coincides with the period of time during which global temperatures appear to have been rising the most steadily – the twentieth century.

Shaidurov’s theory, of course, flies in the face of the more widespread view that the Industrial Revolution of the past 200 years, during which human society unleashed tons of carbon dioxide from the burning of fossil fuels, has triggered the global warming that most scientists believe is underway. Shaidurov says, however, that global temperatures were trending downward prior to a period between 1906-09, a few years before the explosion.

It seems strange to me that an event of this magnitude is mostly known only to science fiction and “X Files” fans. Undoubtedly, this is due purely to the remoteness of this part of the world. If such a thing had landed in Ohio, or Paris, our society would be very different. The memory of such a trauma would reverberate across generations.

Whether or not Tunguska can be blamed for global warming, the event demonstrates that nothing can change history faster than a random chunk of debris from outer space.

I’ll leave to another day the policy impact of Shaidurov’s theory. If this is the cause of global warming, can it be reversed? Will the earth’s upper atmosphere “right” itself, given time? Will Kyoto-type programs help? Geological history certainly suggests that the 5,000 years or so of Earth’s history during which mankind established civilizations and evolved technology has been a period of atypically good weather. Is our luck about to run out? Can our technology help us adjust to what might be an inevitably transformed environment?