Clipmarks | Mohir's 'astronomy' clips

Massive New Object Discovered at Edge of the Solar System

Tue, 19 Aug 2008 20:35:16 GMT

clipped by: Mohir

The Oort Cloud is a spherical cloud of comets believed to lie roughly 50,000 AU, or nearly a light-year from the Sun, which places the cloud at nearly a quarter of the distance to Proxima Centauri, the nearest star to the Sun. The Kuiper belt and scattered disc, the other two known reservoirs of trans-Neptunian objects, are less than one thousandth the Oort cloud's distance. The outer extent of the Oort cloud defines the boundary of our Solar System.

Objects in the Oort cloud are largely composed of ices such as water, ammonia and methane. Astronomers believe that the matter comprising the Oort cloud formed closer to the Sun, and was scattered far out into space by the gravitational effects of the giant planets early in the Solar System's evolution.

Tags: astronomy, solar system

Ice Volcanoes of Titan May Habor Life

Fri, 15 Aug 2008 21:15:21 GMT

clipped by: Mohir
clipper's remarks: For almost thirty years, scientists have known that complex carbon compounds called tholins exist on comets and in the atmospheres of the outer planets. Theoretically, tholins might interact with water in a process called hydrolysis to produce complex molecules similar to those found on the early Earth.

Could tholins formed in Titan's atmosphere react with liquid water temporarily exposed by meteor impacts or ice volcanoes to produce potentially prebiotic complex organic molecules — before the water freezes?

Laboratory research by Catherine Neish, a graduate student working on her doctorate in planetary science at the University of Arizona, suggests, not without controversy, however, that, over a period of days, compounds similar to tholins can be react with water at near-freezing temperatures.

Clip Source: www.dailygalaxy.com

Titan, the sixth and largest moon of the planet Saturn, is thought to be made largely of ice. Some of that ice may melt during meteor impacts or in underground processes, producing "ice volcanoes" that emit a "lava" containing ammonia mixed with water.

New observations of Titan by the Cassini spacecraft suggest the presence of cryovolcanism on the moon's surface. Cryovolcanism has important astrobiological implications, as it provides a means of exposing Titan's organics to liquid water, transforming hydrocarbons and nitriles into more evolved and oxidized prebiotic species.

Ganesa Macula, a mountain on Titan, is believed to be an '"ice volcano" that periodically belches "lava" containing liquid water. Simulated lab research by University of Arizona graduate student Catherine Neish suggests this water may react with organic compounds in Titan's atmosphere to create complex molecules similar to those on the early Earth.

Tags: titan, life, astronomy

Planet and star in puzzling waltz

Fri, 25 Jul 2008 19:56:58 GMT

clipped by: Mohir
clipper's remarks: Instead, the system might have started out that way. "It could be a coincidence, but I don't like explanations based on coincidence," says Aigrain. She suggests that magnetic fields might have helped to lock the system together, but stresses that it is pure speculation at this point.

During its mission, COROT should discover many more planets. Aigrain and her colleagues hope they will then have a better idea whether synchronised systems are common, and what causes the phenomenon.

Clip Source: space.newscientist.com

A newly discovered planet seems to have a surprisingly powerful influence on its parent star, forcing the star to rotate at exactly the same rate as the planet orbits. The planet's day is also the same length, so the pair are fixed in a face-to-face whirl.

The puzzle is how this planet, called COROT-Exo-4b, could have so dominated the vastly larger star, which is bigger than our Sun.

It is fairly close to its parent star, taking only 9.2 days to orbit, but that still puts it further out than most "hot Jupiters". The planet seems too distant to have such a strong influence on the star, says astronomer Suzanne Aigrain of the University of Exeter, UK.

The planet's gravity will raise tides in the fluid body of the star, which would very gradually synchronise the planet's orbit and the star's rotation – but not within the billion-year lifetime of the system. "It would take longer than the age of the universe,"

Tags: astronomy, gravity

Bio-Earth: Are Planets Living Super-Organisms?

Fri, 11 Jul 2008 17:48:23 GMT

clipped by: Mohir
clipper's remarks: He believes that expanding the study of life sciences to the core of our world and the depths of outer space will help us find distant relatives of our own Earth -- planets that could also sustain life.
To explain why contintental plates drift on the surface of the Earth's molten mantle, Maruyama argues that continents actually have life cycles. Old, cold plates on continental fringes sink to “plate graveyards” deep in the Earth’s mantle, and then rise again, creating volcanoes fueled by three-dimensional convection movements deep below the surface.

Clip Source: www.dailygalaxy.com

Japan's Maruyama Shigenori, one of the world's leading geophysicists, is working on a global formula for a vast new field of study that would include dozens of disciplines collaborating to produce an overall picture of the Earth.

Maruyama is creating a new institute called the Center for Bio-Earth Planetology will be launched in 2009 and fully dedicated to creating a new conception of life in space.He wants to find out if the continents will merge again in 250 million years to form a single super-continent; how meteorites change the chemical composition of the Earth; and what the connection is between the temperature of a planet and its magnetic field, which protects plants and animals from being bombarded with cosmic radiation, which in turn influences the rate of mutations and thus the development of new forms of life.

As he connects the dots from astronomy to life sciences, the outlines emerge of an all-encompassing image of entire planets, which appear as living super-organisms.

Tags: planet, gaia, geophysics

Now the Moon reveals its water

Wed, 09 Jul 2008 19:55:56 GMT

clipped by: Mohir

Clip Source: space.newscientist.com

WE THOUGHT it was dry as a bone, but now it seems the moon's parched surface has water hidden beneath it.

Alberto Saal of Brown University in Providence, Rhode Island, and colleagues re-examined lunar volcanic rocks collected in the 1970s during the Apollo 15 and 17 missions. They found up to 50 parts per million of water trapped in tiny spheres of volcanic glass.

That's not much compared with the 500 to 1000 ppm of water in Earth's mantle. Yet when the lava erupted some 3 billion years ago it was exceedingly hot - perhaps up to 7000 °C - so most of the water initially present would have diffused out of the magma, leaving only a small amount by the time it cooled.

They concluded the moon's mantle has between 260 and 700 ppm of water. "This is very surprising, because for 40 years people have studied lunar rocks and no one found any water," says Saal. "We got lucky."

Tags: moon, water, astronomy

New Telescope Array Could Help Detect Possible Signals From Advanced Civilizations

Thu, 05 Jun 2008 11:54:46 GMT

clipped by: Mohir
clipper's remarks: Employing this new equipment in a unique, targeted search for possible civilizations enhances the chances of finding one, in the same way that a search for a needle in a haystack is made easier if one knows at least approximately where the needle was dropped, said Henry, who is speaking about the proposal at the American Astronomical Society annual meeting in St. Louis.
According to the researchers, the critical place to look is in the ecliptic, a great circle around the sky that represents the plane of Earth's orbit. The sun, as viewed from Earth, appears annually to pass along this circle. Any civilization that lies within a fraction of a degree of the ecliptic could annually detect Earth passing in front of the sun. This ecliptic band comprises only about 3 percent of the sky.

Clip Source: www.sciencedaily.com

A Johns Hopkins astronomer is a member of a team briefing fellow scientists about plans to use new technology to take advantage of recent, promising ideas on where to search for possible extraterrestrial intelligence in our galaxy.

They propose to use new Allen Telescope Array, operated as a partnership between the SETI Institute in Mountain View, Calif., and the Radio Astronomy Laboratory at the University of California, Berkeley.

Comprising hundreds of specially produced small dishes that marry modern, miniaturized electronics and innovative technologies with computer processing, the ATA provides researchers with the capability to search for possible signals from technologically advanced civilizations elsewhere in our galaxy -- if, in fact, such civilizations exist and are transmitting in this direction.

Tags: seti, aliens

Astronomy Picture of the Day

Sun, 01 Jun 2008 10:31:53 GMT

clipped by: Mohir

Clip Source: antwrp.gsfc.nasa.gov

Explanation: Each day on planet Earth can have a dramatic ending as the Sun sets below the colorful western horizon. Often inspiring, or offering a moment for contemplation, a sunset is perhaps the single most photographed celestial event. Did you recognize this as a picture of one? The image actually is a single exposure of the setting Sun recorded near Wasserberg, Germany on May 11. To create the uncommon sunset view the photographer used a digital camera and a zoom lens (a lens with an adjustable focal length). During the 1/6 second long exposure he smoothly changed the focal length while simultaneously rotating the camera, altering the image scale and orientation. The result transforms an objective depiction of nature into an artistic abstraction.

Tags: sun, sunset, earth, photography

A (Dark) Matter of Time

Thu, 13 Dec 2007 18:47:28 GMT

clipped by: Mohir

Clip Source: discovermagazine.com

Physicists get creative in their search for dark matter particles

Cosmological experiments suggest dark matter really is out there. Data collected with the Hubble Space Telescope is helping astronomers map dark matter in space along with X-ray pictures of colliding galaxies, measurements of cosmic background radiation, and analysis of the way stars on the ends of galactic arms rotate. Physicists think that dark matter provides a gravitational structure for the Universe, influencing—but not usually interacting with—the matter we perceive. But dark matter isn’t just “out there”—we’re searching for it here on Earth as well.

Though far from established, the most likely dark matter candidates are huge particles called weakly interacting massive particles (WIMPs) or much lighter axion particles. As of yet, no one has been able to detect either—and “no one’s sure they exist,” explains Baer. Here are six schemes that researchers are taking on to find the illusive dark stuff:

Tags: dark matter, astronomy

Copernicus the Surprise Genius

Thu, 13 Dec 2007 18:38:05 GMT

clipped by: Mohir

Clip Source: discovermagazine.com

The man who proved heliocentrism never thought his ideas would amount to much.

Nicolaus Copernicus pioneered the concept of a heliocentric solar system, right? Wrong. Many other astronomers—going back to Aristotle’s time—had proposed the theory. But Copernicus was the first to support it mathematically, according to Jack Repcheck in Copernicus’ Secret: How the Scientific Revolution Began (Simon & Schuster, $25).

In his highly readable book, aimed at lay readers who know little about the history of astronomy, Repcheck draws a portrait of an unusual star of the scientific revolution. Copernicus was not a very focused student: He entered the university four years later than the average student and took nine years longer to graduate. He came from a wealthy family and felt no need to make a name for himself. “Copernicus should have stood no chance of making even a minor mark in astronomy,” Repcheck writes.

Tags: copernicus

Photos: Lightning strikes on Venus

Sun, 02 Dec 2007 13:41:44 GMT

clipped by: Mohir

Clip Source: news.cnet.co.uk

Photos: Lightning strikes on Venus

The Venus Express mission has confirmed that Venus -- with its heavy atmospheric pressure and scalding temperatures -- is not a place you'd want to holiday. Now, lightning has been discovered for the first time, making Venus just the fourth body in the universe known to produce it -- after Earth, Jupiter and Saturn.

The European Space Agency released findings from the Venus Express about the Venusian atmosphere as it's wrapping up its primary mission to study the second rock from the sun. Secondary studies of the planet have been extended for two more Venusian days. That's longer than you might think, as one day on Venus is about 117 Earth days long.

Clip Source: news.cnet.co.uk

Venus Express has also showed how solar winds are stripping away the atmosphere of Venus. Venus would probably be more Earth-like if it possessed a magnetic field similar to Earth's that would prevent its atmosphere from losing gases in the form of ionised particles.

Clip Source: news.cnet.co.uk

Volcanic activity

Tags: venus, astronomy, photos

Largest extrasolar planetary system discovered

Tue, 06 Nov 2007 22:31:33 GMT

clipped by: Mohir

Clip Source: space.newscientist.com

Largest extrasolar planetary system discovered

A fifth planet has been discovered around a nearby star, making it the largest planetary system known outside our own. The planet appears to be a gas giant like Saturn, but scientists say any large moons it may have could potentially host life, since the planet lies in the "habitable" zone around its star, where liquid water can exist.

The planet was discovered around a star called 55 Cancri that is about 41 light years away from Earth and is slightly cooler and dimmer than our own Sun.

The 55 Cancri system was already known to include four other planets, including three giant planets that orbit the star closer than Mercury orbits the Sun. The fourth is four times as massive as Jupiter and orbits at about Jupiter's distance from the Sun.

All of those planets were discovered by the way their gravity tugs on the parent star, a technique called the radial-velocity method.

Tags: plants, astronomy

Big Chunk Of The Universe Is Missing -- Again

Mon, 05 Nov 2007 22:02:35 GMT

clipped by: Mohir

Clip Source: www.sciencedaily.com

Big Chunk Of The Universe Is Missing -- Again

ScienceDaily (Nov. 5, 2007) — Not only has a large chunk of the universe thought to have been found in 2002 apparently gone missing again but it is taking some friends with it, according to new research at The University of Alabama in Huntsville (UAH). The new calculations might leave the mass of the universe as much as ten to 20 percent lighter than previously calculated.

The same UAH group that found what was theorized to be a significant fraction of the "missing mass" that binds together the universe has discovered that some x-rays thought to come from intergalactic clouds of "warm" gas are instead probably caused by lightweight electrons.

If the source of so much x-ray energy is tiny electrons instead of hefty atoms, it is as if billions of lights thought to come from billions of aircraft carriers were found instead to come from billions of extremely bright fireflies.

Tags: universe, astronomy, astrophysics

New radio telescope begins search for alien signals

Thu, 11 Oct 2007 15:39:59 GMT

clipped by: Mohir

Clip Source: space.newscientist.com

New radio telescope begins search for alien signals

The first radio telescope dedicated to the search for extraterrestrial intelligence (SETI) has formally started operations.

The first phase of the Allen Telescope Array, a collection of radio telescopes being built near Hat Creek, California, US, has begun functioning with 42 radio antennas. When complete, the ATA will have 350 dishes, each about 6 metres wide.

Until now, the SETI project has relied on time borrowed from instruments like the Arecibo radio telescope in Puerto Rico, and has had little control over the extent and nature of the observations.

But the ATA will do more than hunt for alien transmissions. The telescope has a large field of view, making it well suited for conducting large-scale surveys of the sky. It will be able to image a circle on the sky as wide as about five Full Moons.

Tags: seti, aliens, astronomy, life

The Dawn Mission, Launching 9-26-07

Sat, 22 Sep 2007 15:05:33 GMT

clipped by: Mohir

Clip Source: www.ponderabout.com

The Dawn Mission, Launching 9-26-07

NASA’s Dawn Mission is scheduled for launch on
Wednesday of this week

the Dawn spacecraft will head towards the solar
system’s asteroid belt, that region between the
orbits of Mars and Jupiter

there, it will seek out and probe the asteroid belt’s
two most massive objects - Ceres and Vesta

[Video]

Ceres , newly designated as a dwarf planet, contains
approximately one third of the total mass of the
asteroid belt

it is spherical in shape and, with respect to its
composition,

the Dawn spacecraft will arrive at Ceres in
February 2015

Vesta is the asteroid belt’s second most massive
object, containing approximately 9% its total mass

it is the solar system’s brightest asteroid; and the
only one that has been visible to the naked eye
from Earth

Vesta is thought to be dry and rocky; having an
iron-nickel core, a rocky mantle, and a surface crust

the Dawn spacecraft is expected to arrive at Vesta
in October of 2011

Tags: astronomy, nasa, asteroid belt, space, solar system

Vera Rubin & Dark Matter

Mon, 10 Sep 2007 15:03:25 GMT

clipped by: Mohir

Clip Source: www.ponderabout.com

Unseen: Vera Rubin & Dark Matter

in 1948, after graduating from Vassar College,
a 20-year-old Vera Rubin tried to enroll at Princeton;
however, she never received the catalog -

women were not permitted in Princeton’s graduate
astronomy program until 1975

there is something ironic about this unacknowledged,
unseen young person going on to establish the
existence of the undetected, unseen substance
that accounts for the vast majority of the mass
of the universe - dark matter

Rubin’s pioneering work on the orbital velocities of
stars in spiral galaxies lead to her discovery of what
is known as the flat rotation curve -

and this is considered to be the most direct evidence
of dark matter

the video below presents Rubin’s work and her
discovery in greater detail

[Video]

the above video is an excerpt from
Stephen Hawking’s Universe

Tags: dark matter, astronomy, gravity