Stories tagged Earth and Space Science

Jun
29
2007

Fallen Trees at Tunguska site: 1927 Kulik expedition
Fallen Trees at Tunguska site: 1927 Kulik expedition
A team of scientists may have finally found a possible impact crater from the Tunguska event that blasted above Siberia nearly a century ago.

Map showing Tunguska event location: Image source: Public Domain
Map showing Tunguska event location: Image source: Public Domain
On June 30, 1908, some sort of extraterrestrial object, such as a comet or an asteroid (at least according to the consensus), exploded in Earth’s atmosphere above the Tunguska River with such force that it flattened more than 2000 square miles of forest. But until now, no viable impact site had ever been found.

This whole Tunguska thing is cloaked in so much mystery and mythology, that agents Muldar and Scully could do a whole X-Files episode about it (in fact, they did). Well, the truth may be out there, but there’s a whole lot of it that remains unknown.

What’s is known is that something big exploded over the Tunguska river region in 1908. The place, unfortunately, is so out-in-the-middle-of-nowhere; it wasn’t scientifically investigated until more than two decades later when mineralogist Leonid Kulik led the first official expedition into the region in 1927. Kulik had initially come upon the site six years earlier when he doing a survey for the Soviet Academy of Sciences. Local eyewitness accounts convinced him that the explosion had been caused by an enormous meteorite impact, and he persuaded the Soviet government to fund the expedition in hopes of salvaging meteoric iron for Soviet industry. But to his disappointment, no possible impact crater was ever located (except in one bare location that later proved to be just a bog). What the expedition did find was a huge area of forest flattened out in a butterfly pattern. Oddly, the only trees still standing were located at ground zero, but those had been stripped bare of all their leaves and bark.

Kulik didn’t find any chunks of iron either, although later expeditions did find microscopic traces of nickel and iron in the soil.

But now, a University of Bologna team of scientists claims that Lake Cheko, which is located just 5 miles north-northwest of the explosion’s epicenter, shows some interesting features that could be interpreted as resulting from some sort of impact, perhaps from a small chunk of the disintegrating space rock – if that’s what it was. The team’s research appears in the online journal Terra Nova.

But other scientists aren’t jumping on the bandwagon just yet. For one thing the lake exhibits almost none of the usual telltale physical markings of an impact crater, other than being uniquely funnel-shaped unlike other neighboring lakes. And even then, its shape is more elliptical than circular. Cheko’s rim is not raised and lacks any sign of upturned ejecta. The scientists have found no shocked terrestrial rock in or around the lake, and to date no meteoric material either. And even if some is found, skeptics say it could have washed into the lake from the surrounding landscape. Also, trees older than a hundred years old are still standing near the lake. If Cheko were an impact crater, the force of the collision would have knocked them all down. It’s true that the lake doesn’t appear on any map prior to 1929, but the region is extremely remote, and there is some folklore evidence of its existence before then.

Other scientists speculate that the source of the event wasn’t from outer space at all, but rather was caused by geophysical forces, such as a cataclysmic gas blow out from deep inside the Earth. It just so happens that the Tunguska event epicenter sets at the intersection of a number of tectonic faults, and atop the ancient crater of a paleovolcano. Kimberlite pipes are also found in the area, an indication of magma reservoirs deep beneath the surface. And evidently there was a lot of earthquake activity in the Tunguska epicenter region back in 1908.
Andrei Ol'khovatov, a former Soviet scientist who is now -in his own words- “an independent researcher/expert” on everything Tunguska, has an entire website addressing this and other possibilities about the event. He has participated in a number of International Tunguska conferences, and I found his site very interesting to peruse.

So, whatever the Tunguska event was, whether it was a comet or asteroid, a UFO, an errant radio transmission, or the real cause of global warning - it exploded about 3-6 miles above the ground, knocked down a whole lot of lumber, scared the dickens out of the locals, and illuminated the sky so brightly it could be seen in London, a third of the way around the globe!

The Italian team plans to return to Lake Cheko in 2008 to perform further tests, including drilling into the core of the lake to examine an anomaly detected some 10 meters below the lake bottom. It could be a meteorite fragment or maybe just some compacted mud. I guess we’ll have to wait and see.

MORE INFO

More on the Tunguska event
The Tunguska event in fiction
BBC website story
Lake Cheko story on Sky& Telescope website

Jun
20
2007

Demoted again: Pluto's ego took another blow this week when it was discovered that dwarf planet Eris is slightly bigger than the former "official" planet. (Drawing courtesy of NASA)
Demoted again: Pluto's ego took another blow this week when it was discovered that dwarf planet Eris is slightly bigger than the former "official" planet. (Drawing courtesy of NASA)
I guess you could call Pluto the Rodney Dangerfield of our solar system…it just doesn’t get any respect.

Last summer Pluto got demoted from an official planet in our solar system and placed in a new category of heavenly bodies: dwarf planets. Now with more research, it’s been determined that Pluto isn’t even among the largest of the dwarves.

Eris is the cause of all of this turmoil of Pluto’s status. That dwarf planet was discovered to have similarities to Pluto and led astronomers to relook at how they define planets. Pluto and Eris were both bumped into the dwarf plant status. Now, the size of Eris has been measured: a diameter of 1,490 to 1,860 miles. Pluto’s diameter is a shade smaller: 1,430 miles.

All of these details came to light after astronomers discovered a moon, Dysnomia, circling Eris. Judging from the speed that Dysonmia has spinning around Eris, researchers have determined that Eris is about 27 percent heavier than Pluto as well. Both dwarf planets are made up primarily of rock and ice.

Don’t worry about any physical effects from this growing dwarf planet rivalry. Eris’ orbit is about twice as far away from the sun as Pluto’s. They’re a quite safe distance apart from each other.

Jun
20
2007

Live video from space

Space shuttle detaches from ISS
Space shuttle detaches from ISS
I have been watching NASA TV which is broadcast live via the internet from the International Space Station and the space shuttle, Atlantis. Atlantis detatched from the ISS last night and is now preparing for its landing tomorrow. On board is Suni Williams, who is the new record holder for a long-duration single spaceflight for a woman.

Failure of two ISS computers added tension.

When two computers which controlled life support and space station positioning failed at the same time, the ten astronauts needed to either fix them or abandon the space station. Internation Space Station, June 2007
Internation Space Station, June 2007
An out of position thermal blanket also need to be repaired before landing. In addition to emergencies, the crew installed the Starboard 3 and 4 (S3/S4) truss segment and conducted four spacewalks to activate the S3/S4 and assist in the retraction of solar array on the Port 6 truss. These large structures may have been what caused the computer glitches.

You can watch, too.

If you have medium high speed internet (mine is 1.5mbps) you can see live video from space. Last night I saw that the Atlantis was passing over the Great Lakes just after sunset so I ran outside to see if I could see them (it wasn't dark enough). Both the Atlantis and the space station will be visible tonight as they pass overhead. The NASA TV launch page is here. I recommend the Windows Media viewer which allows full screen viewing.

Jun
14
2007

Space plane: Here's an artist's rendering of what the proposed space plane would look like. (Photo courtesy of EAS Astrium)
Space plane: Here's an artist's rendering of what the proposed space plane would look like. (Photo courtesy of EAS Astrium)
It’s never too early to plan your next vacation. And I have a trip idea for you.

This week EADS Astrium in Paris announced its plans for a jet plane/rocket that will take passengers on a half-hour trip into outer space, including three minutes of weightlessness. If development plans continue on schedule, the first trips could be made in 2012.

Here’s how the planes work. They will take off from a conventional airport’s runway using standard jet engines. Once the planes get 7.5 miles in the sky, rocket engines will fire to quickly accelerate the craft. How fast? In 80 seconds the plane will be 37 miles above Earth.

You can sit here: For around $200,000 you can buy one of these seats for a 90-minute trip, which includes a half hour in space and three seconds of weightlessness. (Photo courtesy of EAS Astrium)
You can sit here: For around $200,000 you can buy one of these seats for a 90-minute trip, which includes a half hour in space and three seconds of weightlessness. (Photo courtesy of EAS Astrium)
After the rocket blast ends, the plane will coast into a space orbit that will be below satellite traffic, but above airline traffic. Four passengers will be able to ride on each trip which figures to spend about a half hour in space. The plane would then descend back into Earth’s atmosphere, jet engines would kick in and the plane would make a regular landing at an airport, about 1.5 hours after taking off.

Okay, there’s one more small piece of information I need to tell you about. The cost per passenger is estimated at between $199,000 and $265,000. You might need to save some a lot of your sofa change between now and 2012 to come up with that kind of plane fare.

More information about the project is available at www.astrium.eads.net.

Jun
08
2007

NASA's new ride: This artist's rendition shows what the new Orion orbiter and Ares rocket might look like when it takes astronauts and payloads into space. (Photo courtesy of NASA)
NASA's new ride: This artist's rendition shows what the new Orion orbiter and Ares rocket might look like when it takes astronauts and payloads into space. (Photo courtesy of NASA)
Good news!!! NASA announced today that its shuttle replacement timetable has been moved up. The new spacecraft should be ready by 2013, two years faster than earlier predicted. Readers of Science Buzz may remember the story posted back in March about a five-year gap in U.S. space access capabilities.

The current NASA schedule calls for 16 more shuttle flights through 2010. The new proposed spacecraft, Ares rockets and Orion Crew Exploratory Vehicle, will have a lot more carrying capacity than the current shuttle fleet. The Ares V that is proposed could carry five or six times the cargo of the current shuttles.

Jun
04
2007

To the Moon, Alice!: China and India are planning to send probes to Earth's closest neighbor.  (Photo by NASA)
To the Moon, Alice!: China and India are planning to send probes to Earth's closest neighbor. (Photo by NASA)

I don't do a lot of space-related posts. I find outer space kind of boring. But there have been a few stories lately that caught my eye.

Back to the moon

For the last couple of years, there's been talk of the US going back to the Moon. It looks like we might have some company when we get there. China and India recently announced their separate plans to send unmanned probes to the moon. China wants to study the chemical composition of the Moon’s surface, while India plans to create a 3D map of the satellite.

More planets than you can shake a stick at

Scientists at the University of California at Berkely have announced the discovery of 28 more planets outside of our Solar System, bringing the total to 236. They also discovered seven more “brown dwarfs” – which are basically stars that failed to ignite. Some scientists speculate that brown dwarfs may account for the missing “dark matter” whose gravity holds the Universe together.

And finally,

Hi-res Mars images

From the University of Arizona.

Jun
04
2007

NASA Administrator Michael Griffin: What climate is the "best" climate?  (Photo from NASA.)
NASA Administrator Michael Griffin: What climate is the "best" climate? (Photo from NASA.)

Several months ago, political columnist George Will argued that global warming was nothing to worry about. The Earth has warmed and cooled many times before. Even if the current warming is caused by humans (a point which Will is skeptical on), so what? What makes the current climate so special that it needs to be preserved?

Nobody paid much attention at the time. But now NASA administrator Michael Griffin has made a similar pronouncement.

"I have no doubt that a trend of global warming exists.... I am not sure that it is fair to say that it is a problem we must wrestle with. To assume that it is a problem is to assume that the state of Earth's climate today is the optimal climate, the best climate that we could have or ever have had and that we need to take steps to make sure that it doesn't change — I guess I would ask which human beings, where and when, are to be accorded the privilege of deciding that this particular climate...is the best climate for all other human beings."

This statement outraged many scientists, who feel that global warming is a crisis and needs to be dealt with. Griffin later clarified his remarks, saying that NASA’s job is to collect climate information. It does not set policy. Thus, his comments should not be seen as officially endorsing any particular course of action (or inaction).

May
03
2007

A meteor streaking across the night sky: Photo by Jeff Smallwood at flickr.com.
A meteor streaking across the night sky: Photo by Jeff Smallwood at flickr.com.

The Aquarid meteor shower is due to reach its peak this weekend. Clear skies and warm spring temperatures in many parts of the country will make this the first good meteor viewing of the year. The shower is due to peak at 7 am Eastern time on the 5th with meteors falling at a rate of about one per minute. But you can go out any night this weekend after midnight and look low in the eastern sky – you may catch a few falling stars to put in your pocket and save for a rainy day.

You can learn more about meteor showers here.

This site has more kid-friendly information.

And this is a good site for heavy-duty meteor fans.

Apr
20
2007

Hey! National Astronomy Day is April 21, but we're celebrating it a day early this year on Kellogg Plaza! Come look through a telescope at the sun, the moon, Saturn, and the Orion nebula. Help us grind the mirror and assemble a six inch telescope. And come talk to some very committed amateur astonomers from the Minnesota Astronomical Society.

What: National Astronomy Day at the Science Museum
When: Friday, April 20, 10:30 a.m. - 9 p.m.
Where: Kellogg Plaza

Apr
18
2007

Ever wanted to be a storm spotter? Now's your chance! The National Weather Service (NWS) relies on local SKYWARN storm spotters to confirm, from the ground, what meteorologists are seeing on radar. NWS storm spotters are not tornado chasers like the folks in the movie "Twister." Instead, they report wind gusts, hail size, rainfall, cloud formations, and the like to NWS and local emergency management agencies.

Tornado: This tornado, seen in its early stages of formation over Union City, Oklahoma (May 24, 1973), was the first one caught by the National Severe Storms Laboratory doppler radar and chase personnel. (Photo courtesy NOAA Photo Library, NOAA Central Library; OA
Tornado: This tornado, seen in its early stages of formation over Union City, Oklahoma (May 24, 1973), was the first one caught by the National Severe Storms Laboratory doppler radar and chase personnel. (Photo courtesy NOAA Photo Library, NOAA Central Library; OA

New radar equipment is still not sensitive enough to determine the existence of an actual tornado. It can only predict where severe weather is likely to occur. So the NWS needs trained volunteers to verify actual severe weather.

With peak storm season just around the corner (mid-June here in the Upper Midwest), free, 2.5-hour classes are being offered to train new SkyWarn volunteers.

SkyWarn class schedule, greater Minnesota
SkyWarn class schedule, Twin Cities Metro area

Here's how you get started...