Weird Science Stuff: June 2012

1969 Fireball Meteorite Reveals New Ancient Mineral

from:

By Jeanna Bryner, LiveScience Managing Editor | LiveScience.com – Wed, Jun 27, 2012

A fireball that tears across the sky is not just a one-time skywatching event — it can reap scientific dividends long afterward. In fact, one that lit up Mexico's skies in 1969 scattered thousands of meteorite bits across the northern Mexico state of Chihuahua. And now, decades later, that meteorite, named Allende, has divulged a new mineral called panguite.

Panguite is believed to be among the oldest minerals in the solar system, which is about 4.5 billion years old. Panguite belongs to a class of refractory minerals that could have formed only under the extreme temperatures and conditions present in the infant solar system.

The name of the titanium dioxide mineral, which has been approved by the International Mineralogical Association, honors Pan Gu, said in Chinese mythology to be the first living being who created the world by separating yin from yang (forming the earth and sky). [Infographic: The Science of Meteorites]

"Panguite is an especially exciting discovery since it is not only a new mineral, but also a material previously unknown to science," study researcher Chi Ma, a senior scientist at Caltech, said in a statement.

Until now, panguite had neither been seen in nature nor created in a lab. "It's brand-new to science," Ma told LiveScience in an interview.

The scientists used a scanning-electron microscope to view the panguite within a so-called ultra-refractory inclusion embedded within the meteorite. Inclusions are the minerals that get trapped inside meteorites as they are forming. The ultra-refractory type includes minerals that can resist high temperatures and other conditions in extreme environments, such as those thought to exist as our solar system was forming.

High-tech lab analyses revealed panguite's chemical composition and crystal structure, which Ma said is new, and as such, could be explored for novel engineering materials.

The Allende meteorite, where the mineral was hidden, is the largest of a class of carbonaceous chondrites found on Earth. Chondrites are primitive meteorites that scientists think were remnants shed from the original building blocks of planets. Most meteorites found on Earth fit into this group. (When meteors hit the ground they are called meteorites.)

Before they reach terra firma, most meteorites are fragments of asteroids (space rocks that travel through the solar system), while others are mere cosmic dust shed by comets. Rare meteorites are impact debris from the surfaces of the moon and Mars. The Allende meteorite likely came from the asteroid belt between Mars and Jupiter, scientists say.

Studying panguite and other components of the Allende meteorite are essential for understanding the origins of the solar system, Ma said. In fact, Ma's team has discovered nine new minerals, including panguite, in the Allende space rock.

The new mineral is detailed in the July issue of the journal American Mineralogist.

Leap Second on Saturday Will Cause 61-Second Minute

from Yahoo Canada:

The transition from June to July will be delayed by circumstances beyond everyone's control. Time will stand still for one second on Saturday evening (June 30) because a "leap second" will be added to let a lagging Earth catch up to super-accurate clocks.

International Atomic Time is a very accurate and stable time scale. It is a weighted average of the time kept by about 200 atomic clocks in over 50 national laboratories worldwide. Atomic time is measured through vibrations of atoms in a metal isotope that resembles mercury and can keep time to within a tenth of a billionth of a second per day. The result is extremely accurate time that can be used to improve synchronization in precision navigation and positioning systems, telecommunications networks and deep-space communications.

But from their careful observations of the positions of the stars, astronomers have deduced that Earth's rotation is ever so slightly slowing down at a non-uniform rate, probably attributable to its sloshing molten core, the rolling of the oceans, the melting of polar ice and the effects of solar and lunar gravity.

Adjusting the clock

Today's atomic clocks are accurate to approximately one second in 200 million years. On average, our planet has been falling behind atomic time at a rate of about two milliseconds per day. As a result, it now trails the "official" clock by about six-tenths of a second.

As a result of this difference, atomic clocks, which are used to set all other clocks, can get out of sync with the Earth and periodically have to be adjusted. A leap secondhas to be added from time to time to make up the difference.

The next time will be Saturday, when the master clock at the United States Naval Observatory will be adjusted at 7:59:60 p.m. Eastern Daylight Time, or 23:59:60 Coordinated Universal Time (UTC). This will put Mother Earth about four-tenths of a second ahead of the clock, giving her a bit of a head start as we transition into the new month of July.

Who says chivalry is dead?

How to see and hear the extra second

Today many retailers market radio clocks as "atomic clocks." Though the radio signals these clocks receive usually come from true atomic clocks, they are not atomic clocks themselves. Typical radio "atomic clocks" require placement in a location with a relatively unobstructed atmospheric path to the transmitter, need reasonably good atmospheric conditions to receive the time signals, and perform synchronization once a day, during the nighttime. [Hit Snooze: 10 Best Alarm Clocks]

If you own such a device, you may want to observe what your clock displays just before 0 hours GMT July 1, which corresponds to 8 p.m. EDT on June 30. The minute beginning at 7:59 p.m. EDT will contain 61 seconds. (When a leap second was added in 2005, I watched my own clock closely during that minute as the seconds ticked off. When the final second of that minute was reached, the number "59" flashed not once, but twice!)

If you don't have a radio clock, you can bring up a time display on your computer by going to:http://nist.time.gov/.

You can also listen for the leap second by tuning in to a shortwave time signal station. In North America, the "extra tick" can be heard by listening to either station WWV in Fort Collins, Colo., at 2.5, 5, 10, 15 and 20 megahertz; WWVH in Kekaha, Hawaii, at 2.5, 5, 10 and 15 megahertz; or CHU in Ottawa, Ontario, Canada, at 3330, 7850, and 14670 kilohertz. A listing of shortwave time signal stations for other parts of the world can be found at http://www.dxinfocentre.com/time.htm.

Should you encounter poor reception, try preparing a seconds pendulum by hanging a small weight on a string about 39.1 inches (99.3 centimeters) long. Adjust the string length beforehand until the swings exactly match the time signal ticks. If the beeps denoting the start of each minute occur at the left extreme of a swing before the final (UTC) minute of June, they will be heard at the right extremes thereafter. (Although the swing amplitude will be steadily dying down, this does not affect a free pendulum's oscillation period.)

Not the year's midpoint

Saturday will be the 25th time a leap second has been needed since the practice was initiated in 1972, and will be the first in 3½ years. The most recent leap second was inserted into the atomic time scale on New Year's Eve of 2008.

Incidentally, July 1 is not the midpoint of 2012. That will take place July 2 at 0 hours UTC if you count the year as beginning when it did at Greenwich, England – or at 1 a.m. Daylight Saving Time, if you count the year as beginning when your clock said midnight in the standard time of your time zone, .

Regardless of how you use your extra second, just keep this one indisputable fact in mind: Whenever you note the time on the clock, realize that it is now – right now – later than it has ever been.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

Scientists to produce first 3-D models of Arctic sea ice

from Yahoo Canada:

Scientists working with Greenpeace will undertake an expedition to the Arctic that will produce the first 3D models of the Arctic sea ice, the group said on Friday.

The team was due to leave on Friday for the icy north from the Norwegian archipelago of Svalbard.

"Starting on July 9, scientists led by Peter Wadhams of Cambridge University will work together with 3D scanning experts and engineers to capture the true shape of Arctic sea ice for the first time," Greenpeace said in a statement.

Scientists will use a special submarine vehicle to measure underwater icebergs and surface laser scanners for the exposed parts.

The finished model will pinpoint pressure ridges and deformations resulting from the repeated melting and freezing of the ice.

"The emphasis on pressure ridges is because these ice deformation features -- which can be as much as 50 metres deep -- contain about half of the ice in the Arctic, yet have been shrinking in numbers and thickness much faster than the ice as a whole," said Wadhams.

"We need to see if they are melting, or disintegrating, or both."

Greenpeace will also use the exhibition to draw attention to its Save The Arctic campaign, launched on the sidelines of the Rio+20 Earth summit last week to preserve the land mass from oil exploration and industrial fishing.

A number of celebrities including actors Hugh Grant and Penelope Cruz, entrepreneur Richard Branson and singer Paul McCartney have already signed a petition which will be placed at the North Pole.