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Wednesday, 20 August 2008

Space news, everyone!

Space fans, here we go again. Few exciting news about space exploration and also a cool video that recorded the sounds of the icebergs. I find it very funny and interesting.

  1. Embracing icebergs sing eerie duets
  2. Makemake Is Named the Newest Plutoid
  3. Video Shows Moon From Other Side
  4. Solar sail gets another chance for launch
  5. Almighty smash left record crater on Mars
If you wonder why the Iceberg stuff is on the top, it's because I really want you to watch the video.

Embracing icebergs
sing eerie duetsMovie Camera

  • 12:22 09 July 2008
  • Nora Schultz

They travel from Antarctica to Tahiti, can sound like laughing monkeys, or barking dogs, and some were triggered by the December 2004 tsunami: they are the eerie songs made by some of Antarctica's largest icebergs.

The phenomenon occurs when the huge lumps of ice scrape past each other and produce thousands of tiny "icequakes". These are so similar to earthquakes, researchers say, that icebergs could help to better understand and predict tremors.

Massive tabular icebergs break off the Antarctic ice shelf about every 50 years. Soon after the last "calving" event in 2000, unusual harmonic tremors were picked up by underwater hydrophones as far as Tahiti.

Emile Okal of Northwestern University in Evanston, Illinois, and colleagues soon traced the sounds back to the new icebergs, including what was then the world's largest free-floating berg, B15A.

To find out how the icebergs produce the noises, Doug MacAyeal at the University of Chicago and colleagues constructed a network of seismographs on iceberg C16, which at the time was aground in the Ross Sea and adjoining to B15A.

They monitored the tremors – which are inaudible to the human ear, but can be heard if the recordings are speeded up – during the austral summer of 2003.

The team found that one particular song was repeated by the giants daily, and the timing matched that of the tides in the Ross Sea. It began vigorously on the first surge then slowly ground to a halt and began again when the tide reversed.

The researchers triangulated the source of the tremors and discovered that they came from an area where C16 was rammed by B15A in a collision zone only a few kilometres long. Pushed by the daily tides, the bergs scraped past each other in many brief, jerky movements.

The researchers say the icebergs could allow them to study earthquakes in a laboratory-like setting.

"It turns out that these icebergs are perfect analogies of plate tectonics. They float on the ocean like surface plates float on magma; and just like them, they occasionally collide and slide against each other," says MacAyeal.

"For example, the pattern after the tidal pause, when the contact zone breaks again after briefly refreezing, might help people understand why the first earthquake after a long delay is so much stronger," he says. "The iceberg tremors could also lead to ways to predict the strength of aftershocks."

MacAyeal has played with the speed of recordings to produce sounds "which speak to the human ear". In one instance, the bergs "bark" like a dog, elsewhere they "ping" like a submarine (see video, right).

The seismometers also recorded the break-up of B15A in 2005, producing a sound similar to a laughing monkey.

Daniela Jansen at the University of Swansea, UK, says it could be useful to record similar tremors on the Larsen C ice shelf.

Once this ice shelf breaks up catastrophically, like its cousins Larsen A and B have before, the tremor data could help to pinpoint where the disintegration started. This could help understand the connection between ice shelf break-up and climate warming.

Journal reference: Journal of Geophysical Research (DOI: 10.1029/2008JF001005, in press) source

My comment: The video is hilarious. Or ok, wrong word. It's just very exciting to hear 2 icebergs rubbing each other. It reminds me of the Earth humming. It looks like we're immersed by sounds, which is so cool. And also, do you realise that sound and the earthquakes seismic waves are basically the same thing- pressure waves :) That's so cool!

Makemake Is Named the Newest Plutoid

Published: July 20, 2008

WASHINGTON (Reuters) — A dwarf planet orbiting beyond Neptune has been designated the third plutoid in the solar system and given the name Makemake, the International Astronomical Union said Saturday.

The red methane-covered dwarf planet, formerly known as 2005 FY9 or “Easterbunny,” is named after a Polynesian creator of humanity and god of fertility.

Just last month the astronomical union, which names planets and other heavenly bodies, decided to create a class of subplanets called plutoids.

Pluto, demoted from planet status, and Eris are the other two plutoids.

Makemake is slightly smaller and dimmer than Pluto and was discovered in 2005.

“The orbit is not particularly strange, but the object itself is big, probably about two-thirds the size of Pluto,” said Michael E. Brown of the California Institute of Technology, who discovered and named Makemake (pronounced MAH-keh MAH-keh).

Dr. Brown said the name came to him when he was looking for a mythological god and thought of Easter Island in the South Pacific. Makemake was the chief god among people who settled the island. source

My comment: Nice, another non-planet around. I don't see why they cannot be planets. I mean, what's so special in the term "planet". And they are not so small after all. Anyway, I hope the naming brings us good fortune.

Video Shows Moon From Other Side

July 19, 2008

A NASA spacecraft designed to look for comets turned its cameras homeward, capturing a unique view of the moon passing in front of the Earth as seen from 31 million miles away. The spacecraft, Deep Impact, took shots at 15-minute intervals, which were combined to make the sequence shown below.

The latest images show the moon and Earth in greater detail than previous ones taken by orbiting spacecraft, showing oceans and continents on our planet and craters on the moon. By studying how Earth looks from so far away, the scientists hope to sharpen their search for alien worlds that may share similar characteristics.

Sara Seager, a planetary theorist at the Massachusetts Institute of Technology and a co-investigator on the extended mission for Deep Impact, notes that the data being gathered are just for planning purposes because the discovery of a good candidate alien planet is a long way off in the future.

But should that time come, by comparing this detailed image of Earth to a glimmering, flickering point source of light, “we want to be able to infer whether there are oceans and continents on another planet,” she said. — SARAH GRAHAM source

My comment: Eh, far in the future my ass. I bet it would happen in 5 years or less. But the video is cool.

Solar sail gets another chance for launch

  • 04 July 2008
A four-quadrant solar sail propulsion system – similar to the one to be tested from NanoSail-D – hovers with payload at a fixed point in space in Earth orbit (Illustration: NASA/MSFC)
A four-quadrant solar sail propulsion system – similar to the one to be tested from NanoSail-D – hovers with payload at a fixed point in space in Earth orbit (Illustration: NASA/MSFC)

IT'S an idea that has been plagued by misfortune. Now, proponents of technology that seeks to propel spacecraft using the pressure exerted by photons from the sun on thin "solar sails" look set for another chance to get their idea off the ground.

Missions by the US non-profit Planetary Society to test solar sail technology failed in 2001 and 2005, because the rockets needed to get them into space malfunctioned. Now they look set for a comeback as early as 29 July, when a tiny NASA spacecraft called NanoSail-D is scheduled to go into Earth orbit.

The aim is to demonstrate the feasibility of deploying sails in orbit. The spacecraft will unfurl four 3-metre-wide sails made of plastic film coated with aluminium. In addition to feeling pressure from sunlight, it is hoped that the sails will experience a slight drag from Earth's outer atmosphere. Similar sails could one day be used to bring normal satellites back to Earth after their missions, reducing orbital clutter.

The spacecraft will unfurl four sails made of plastic film coated with aluminium

Worryingly, the launcher for the spacecraft, Falcon 1, has suffered similar bad fortune. On its two launch attempts so far, it failed to reach orbit. source

My comment: That sounds so much as a sabotage. But sooner or later, it would fly. And I think that technology could have success, especially when we're not really looking for speedy deploy. I mean if you want to just fly around a detector in the Solar System, what a better way. Well, it won't be particularly quick, but it would spead up with time, having in mind there's no real friction. And it would be fun.

Almighty smash left record crater on Mars

  • 25 June 2008
An impact by an object more than half as wide as Mercury is thought to have created a crater that covers most of Mars's northern hemisphere (Courtesy of S Lombeyda/ M Marinova/ O Aharonson)
A giant impact explains why Mars's two hemispheres are so different (Illustration: Jeff Andrews-Hanna)
A giant impact explains why Mars's two hemispheres are so different (Illustration: Jeff Andrews-Hanna)

EVERY scar tells a story, yet a huge gash on Mars has long proven very hard to read. Now a peek beneath the planet's surface reveals that the scar is the largest known impact structure in the solar system - gouged out by a collision that reshaped the Red Planet.

The surface of Mars's northern hemisphere lies about 6 kilometres lower than that of the southern hemisphere. This has greatly influenced the planet's evolution, says Jeffrey Andrews-Hanna of the Massachusetts Institute of Technology.

The northern hemisphere's thinner crust means more magma has been able to push to the surface to fuel volcanism, and the difference in altitude meant that ancient outbursts of liquid water tended to flow from south to north.

It also means that atmospheric pressure on northern surfaces is higher than in the south, encouraging winds there to scour the surface more than in the opposite hemisphere. As a result, it seems likely that more dust has been blown from north to south than the other way.

A prime theory to explain how this global asymmetry came about is that a huge impact blasted away much of the northern hemisphere's crust. The prime suspect in the hunt for clues to such a collision had been an extensive structure in the northern hemisphere, thought to have formed about 4.4 billion years ago.

This timing fits with other evidence that numerous large projectiles were careening through the inner solar system at this time, such as the Mars-sized planet that walloped the primordial Earth and formed our Moon, yet left no trace on Earth.

The timing fits - numerous large projectiles were careening through the inner solar system 4.4 billion years ago

However, the Mars impact theory has been undermined by the structure's irregular, kidney shape, since an impact would have punched out a circle or ellipse.

To examine the suspected crater in more detail, Andrews-Hanna and colleagues analysed variations in the strength of gravity above the Martian surface using NASA's Mars Reconnaissance Orbiter. This revealed that the structure was actually a near-perfect ellipse, but ended up looking kidney-shaped because lava has since obscured part of it (scroll down for image).

At roughly 8500 by 10,600 kilometres across, it is nearly 15 times the area of the Moon's South Pole-Aitken basin which, at 2500 kilometres in diameter, is the largest undisputed impact scar in the solar system.

The Mars crater was probably created by an object as large as 2700 kilometres across - over half of the diameter of Mercury. The effects of such an impact would have been catastrophic, says Andrews-Hanna.

"Within the basin you'd have had a magma ocean - it would have been easily several tens of kilometres deep," he says. "Outside the basin you would have had a tremendous amount of ejecta raining back down on the surface."

Herbert Frey of NASA's Goddard Space Flight Center in Greenbelt, Maryland, had been sceptical of the giant impact theory because of the structure's irregular shape, but now calls it the "best working hypothesis" to explain the differences between the Red Planet's hemispheres. "They make a compelling case," he says.

Journal reference: Nature (vol 453, p 1216) source

My comment: No comment, really! The magnitude of the events is just leaving me speachless. I think the theory sounds plausible.

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