Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




VENUSIAN HEAT
The Mysterious Arc of Venus
by Dr. Tony Phillips for NASA Science News
Huntsville AL (SPX) Jun 05, 2012


The Arc of Venus observed during the planet's 2004 transit by amateur astronomer Andre Rondi using a 10-cm refractor near Toulouse, France.

When Venus transits the sun on June 5th and 6th, an armada of spacecraft and ground-based telescopes will be on the lookout for something elusive and, until recently, unexpected: The Arc of Venus. "I was flabbergasted when I first saw it during the 2004 transit," recalls astronomy professor Jay Pasachoff of Williams College. "A bright, glowing rim appeared around the edge of Venus soon after it began to move into the sun."

For a brief instant, the planet had turned into a "ring of fire."

Researchers now understand what happened. Backlit by the sun, Venus's atmosphere refracted sunlight passing through layers of air above the planet's cloudtops, creating an arc of light that was visible in backyard telescopes and spacecraft alike.

It turns out, researchers can learn a lot about Venus by observing the arc. Indeed, it touches on some of the deepest mysteries of the second planet.

"We do not understand why our sister planet's atmosphere evolved to be so different than Earth's," explains planetary scientist Thomas Widemann of the Observatoire de Paris.

Earth and Venus are similar distances from the sun, are made of the same basic materials, and are almost perfect twins in terms of size. Yet the two planets are wrapped in stunningly dissimilar blankets of air. Venus's atmosphere is almost 100 times more massive than Earth's and consists mainly of CO2, a greenhouse gas that raises the surface temperature to almost 900F.

Clouds of sulfuric acid tower 14 miles high and whip around the planet as fast as 220 mph. A human being transported to this hellish environment would be crushed, suffocate, desiccate, and possibly ignite.

For the most part, planetary scientists have no idea how Venus turned out this way.

"Our models and tools cannot fully explain Venus, which means we lack the tools for understanding our own planet," points out Widemann. "Caring about Venus is caring about ourselves."

One of the biggest mysteries of Venus is super-rotation. The whole atmosphere circles the planet in just four Earth days, much faster than the planet's spin period of 243 days. "The dynamics of super-rotation are still a puzzle despite a wealth of data from landmark missions such as NASA's Pioneer Venus, Russia's Venera and VEGA missions, NASA's Magellan and more recently ESA's Venus Express."

This is where the Arc of Venus comes in. The brightness of the arc reveals the temperature and density structure of Venus's middle atmosphere, or "mesosphere," where the sunlight is refracted.

According to some models, the mesosphere is key to the physics of super-rotation. By analyzing the lightcurve of the arc, researchers can figure out the temperature and density of this critical layer from pole to pole.

When the arc appeared in 2004, the apparition took astronomers by surprise; as a result, their observations were not optimized to capture and analyze the fast-changing ring of light.

This time, however, they are ready. Together, Pasachoff and Widemann have organized a worldwide effort to monitor the phenomenon on June 5th, 2012. "We're going to observe the arc using 9 coronagraphs spaced around the world," says Pasachoff. "Observing sites include Haleakala, Big Bear, and Sacramento Peak. Japan's Hinode spacecraft and NASA's Solar Dynamics Observatory will also be gathering data."

Pasachoff has some advice for amateur astronomers who wish to observe the arc. "The best times to look are ingress and egress--that is, when the disk of Venus is entering and exiting the sun. Ingress is between 22:09 and 22:27 UT on June 5th; egress occurs between 04:32 and 04:50 UT. Be sure your telescope is safely filtered. Both white light and H-alpha filters might possibly show the arc."

.


Related Links
The 2012 Transit of Venus
Venus Express News and Venusian Science






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





VENUSIAN HEAT
James Cook and the Transit of Venus
Huntsville AL (SPX) Jun 04, 2012
Every ~120 years a dark spot glides across the Sun. Small, inky-black, almost perfectly circular, it's no ordinary sunspot. Not everyone can see it, but some who do get the strangest feeling, of standing, toes curled in the damp sand, on the beach of a South Pacific isle.... City odors drifted in from Plymouth, across the ship, shoving aside the salt air. Sea gulls fluttered upward, screec ... read more


VENUSIAN HEAT
UA Lunar-Mining Team Wins National Contest

NASA Lunar Spacecraft Complete Prime Mission Ahead of Schedule

NASA Offers Guidelines To Protect Historic Sites On The Moon

Neil Armstrong gives rare interview - to accountant

VENUSIAN HEAT
Wind may have driven avalanches on Martian dunes

On The Hunt For Light-Toned Veins Of Gypsum

Mars missions may learn from meteor Down Under

Waking Up with the Sun's Rays

VENUSIAN HEAT
European Union launches latest space regulation efforts

CU-Boulder students to help NASA develop plant food production for deep space

China calls for inclusive development of outer space

New Moon for India

VENUSIAN HEAT
What will China's Taikonauts do aboard Tiangong 1?

Why is China sending a woman into space?

China launches telecommunication satellite

Tiangong 1 Ready To Meet Shenzhou 9

VENUSIAN HEAT
Capillarity in Space - Then and Now, 1962-2012

Dragon on board

SpaceX Launches Falcon 9 Dragon on Historic Mission

SpaceX Dragon Transports Student Experiments to Space Station

VENUSIAN HEAT
Another Ariane 5 begins its initial build-up at the Spaceport

Boeing Receives DARPA Airborne Satellite Launch Study Contract

Sea Launch Delivers the Intelsat 19 Spacecraft into Orbit

SpaceX Dragon capsule splash lands in Pacific

VENUSIAN HEAT
Tiny Planet-Finding Mirrors Borrow from Webb Telescope Playbook

Astronomers Probe 'Evaporating' Planet Around Nearby Star with Hobby-Eberly Telescope

Venus transit may boost hunt for other worlds

NSO To Use Venus Transit To Fine-Tune Search For Other Worlds

VENUSIAN HEAT
Samsung vows US launch of Galaxy despite Apple suit

Repelling the drop on top

Elvis Lives! US firm to create 'virtual' Presley

Taiwan's HTC denies Microsoft snub over Windows 8




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement