Science & TechnologyS


Telescope

Massive Galaxies Caught In The Act Of Merging

Astronomers have caught multiple massive galaxies in the act of merging about 4 billion years ago. This discovery, made possible by combining the power of the best ground- and space-based telescopes, uniquely supports the favoured theory of how galaxies form.

Composite colour-image of the brightest galaxies
©ESO
Composite colour-image of the brightest galaxies in four groups located about 4 billion light-years away. The galaxies are ordered in increasing stellar mass, i.e. a rough time sequence (upper left, upper right, lower left, lower right).

How do galaxies form? The most widely accepted answer to this fundamental question is the model of 'hierarchical formation', a step-wise process in which small galaxies merge to build larger ones. One can think of the galaxies forming in a similar way to how streams merge to form rivers, and how these rivers, in turn, merge to form an even larger river. This theoretical model predicts that massive galaxies grow through many merging events in their lifetime. But when did their cosmological growth spurts finish? When did the most massive galaxies get most of their mass?

To answer these questions, astronomers study massive galaxies in clusters, the cosmological equivalent of cities filled with galaxies. "Whether the brightest galaxies in clusters grew substantially in the last few billion years is intensely debated. Our observations show that in this time, these galaxies have increased their mass by 50%," says Kim-Vy Tran from the University of Zürich, Switzerland, who led the research.

Info

Human exoskeleton suit helps paralyzed people walk

Haifa, Israel - Paralyzed for the past 20 years, former Israeli paratrooper Radi Kaiof now walks down the street with a dim mechanical hum.

That is the sound of an electronic exoskeleton moving the 41-year-old's legs and propelling him forward -- with a proud expression on his face -- as passersby stare in surprise.

Image
©REUTERS/Baz Ratner
Radi Kaiof walks using an electronic exoskeleton at a development center in the northern city of Haifa August 18, 2008. The device, called ReWalk, slated for commercial sales in 2010, consists of motorised leg supports, body sensors and a back pack containing a computerised control box and rechargable batteries. It also requires crutches to help with balance. Picture taken August 18, 2008.

Magnify

Flashback Longest underground river found near Mexican coast

Cave divers in Mexico's Yucatan peninsula have discovered what may be the world's longest underground river, connecting two cave systems with a waterway at least 95 miles (154 km) long.

A group of foreign divers exploring the area near the Caribbean beach resort of Playa del Carmen have yet to name the stretch, but believe it could be connected to two other major systems, adding more than 125 miles (200 km) to its length.

Sherlock

Portal to Maya Underworld Found in Mexico?

A labyrinth filled with stone temples and pyramids in 14 caves - some underwater - have been uncovered on Mexico's Yucatán Peninsula, archaeologists announced last week.

The discovery has experts wondering whether Maya legend inspired the construction of the underground complex - or vice versa.

According to Maya myth, the souls of the dead had to follow a dog with night vision on a horrific and watery path and endure myriad challenges before they could rest in the afterlife.

In one of the recently found caves, researchers discovered a nearly 300-foot (90-meter) concrete road that ends at a column standing in front of a body of water.

X

Anti-Russian Techno Craze: Eight million people at risk of ID fraud after credit card details are stolen by hotel chain hackers

Up to eight million people are at risk of ID fraud after a hacker breached the security system of the world's largest hotel chain.

An Indian hacker broke into the IT system of Best Western Hotel Group and stole personal details of everyone who has stayed there in the past 12 months.

The details, which included home addresses, phone numbers, place of employment and credit card details, were sold on through an underground network controlled by the Russian Mafia.

The information is thought to be worth up to £2.8billion. Experts say that if it falls into the wrong hands it could spark a 'major crimewave'.

Hourglass

Alpine melt reveals ancient life

Melting alpine glaciers are revealing fascinating clues to Neolithic life in the high mountains.

Schnidejoch glacier
©University of Berne
The Schnidejoch glacier records human activity in the region

Hourglass

Ancient city in western Turkey waits to be unearthed

An ancient city in western Turkey, discovered by smugglers of ancient artifacts at an illegal excavation six years ago and recovered with soil by officials, now waits to be unearthed.

Meteor

Australian researcher 'saves the world'

An Australian researcher has won an international prize for her plan to wrap a giant asteroid with reflective sheeting to stop it colliding with the earth and destroying all life.

Such an impact would have the force of 110,000 Hiroshima atomic bombs if the asteroid, which actually exists, hits the planet in 2036, said Mary D'Souza, a PhD student with the University of Queensland's School of Engineering.

Comment: And what about the asteroids that we might not see... in time?


Telescope

Liquid Water in the Martian North

Perchlorate. Never heard of it? Join the club. But NASA's Phoenix spacecraft has found it in the soil in the icy northern plains of Mars. And now that it's been found, scientists are scrambling to explain how it got there, and what, if anything, its presence means about the habitability of the Martian north.

Image
©Unknown
A 3D rendering of a perchlorate ion, which contains one chlorine atom (green) and four oxygen atoms (red).

Phoenix didn't go to Mars to find perchlorate. It went looking for evidence of liquid water. From orbit, NASA's Mars Odyssey in 2002 discovered water ice in the martian north, lying just inches beneath the surface. Very cold, very hard ice. Far too cold to support life.

But Mars's polar regions aren't always so cold. The angle at which Mars tilts changes over time, and every hundred thousand years or so the planet leans so far over that its north and south poles take turns facing the sun as the planet travels through its orbit.

When this happens, the polar regions get increased sunlight, and some of the subsurface ice may melt, and leave behind telltale mineral signs in the martian soil. Those signs are what Phoenix is looking for.

NASA's MER rovers have both found evidence, at sites near the martian equator, of rocks that were altered by the action of liquid water. But most scientists agree that those alterations occurred quite early in Mars's history, perhaps as long ago as 4 billion years.

Info

Genome Of Simplest Animal Reveals Ancient Lineage

As Aesop said, appearances are deceiving-even in life's tiniest critters. From first detection in the 1880s, clinging to the sides of an aquarium, to its recent characterization by the U.S. Department of Energy Joint Genome Institute (DOE JGI), a simple and primitive animal, Trichoplax adhaerens, appears to harbor a far more complex suite of capabilities than meets the eye.

Trichoplax adhaerens
©Ana Signorovitch, Yale University
Trichoplax adhaerens

The findings, reported in the August 21 online edition of the journal Nature, establish a group of organisms as a branching point of animal evolution and identify sets of genes, or a "parts list," employed by organisms that have evolved along particular branches.

With each sequenced genome, another dataset is made available to advance the quest of evolutionary biologists seeking to reconstruct the tree of life. The analysis of the 98 million base pair genome of Trichoplax (literally "hairy-plate") illuminates its ancestral relationship to other animals.

Trichoplax is the sole member of the placozoan ("tablet," or "flat" animal) phylum, whose relationship to other animals, such as bilaterians (humans, flies, worms, snails, et al) and cnidarians (jellyfish, sea anemones, corals, et al), and sponges is contentious.