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අභ්‍යවකාශයේ කළු කුහර

shehan123 — Fri, 27 Jan 2012 18:03:50 +0000

විද්‍යාඥයන් විශ්වාස කරන්නේ අභ්‍යවකාශයේ සමහර තැනක ගුරුත්වය කෙතරම් ප‍්‍රබල ද යත් අති දැවැන්ත රික්තක ශෝධකයක් (vacuum cleaner) මෙන් ඒ අසළට එන හැම දෙයක් ම, ඒ කියන්නෙ ඕනෑම පදාර්ථයක් උරා ගන්නවා, එහෙමත් නැත්නම් ගිල ගන්නවා කියලයි. සමහර විට තරුවක්, වල්ගා තරුවක් හෝ ග‍්‍රහ ලෝකයක් හෝ වාත වලාවක් වෙන්න පුළුවන්. ඒවා කොතරම් විශාල වුනත් ඒවායේ ප‍්‍රමාණය ගැන ප‍්‍රශ්නයක් නැහැ. අප ජීවත්වන මේ පොළොව ඇතුළු මුළු සෞරග‍්‍රහ මණ්ඩලය ම වුනත් ගිලගන්න මහ වෙලාවක් යන්නෙ නැහැ. මේ අද්භූත තැන් හැඳින්වෙන්නේ කළු කුහර කියලයි. මේවා ඇසට පෙනෙන්නේ නැහැ. මේවා තමන්ට හසුවන ආලෝකයක් වුවත් උරා ගෙන ගිල ගන්නවා. ඒ අලෝකයට ඉන්පසු එළිය විහිදුවීම කරන්න බැහැ. මෙසේ ගිල ගැනීමේ දී එහි ස්කන්ධය හැකිළෙනවා. ඝනත්වය අනන්තයට පත් වෙමින් සදහටම නොපෙනී යනවා. මේ විදියට අති ප‍්‍රබල ගුරුත්වාකර්ෂණයකින් ඒ අසලට එන ආලෝකය පවා ගිල ගන්නා නිසයි, මේවා කළු කුහර (Black Hole) යනුවෙන් හැඳින්වෙන්නේ. මෙවැන්නක පවතින ගුරුත්වය කෙතරම් ප‍්‍රබල එකක් ද යත් එයින් කාලය හා අවකාශය කෙරෙහි බලපෑමක් එල්ල කෙරෙනවා. කාලයේ වේගය අඩු කරනවා, අවකාශය පුළුල් කර විදහනවා. ඒ නිසා මේ තත්වය අභ්‍යවකාශයේ හමුවන සුවිශේෂී එකක් ලෙස සැලකෙනවා.

මුලින්ම කළු කුහරවලට නම දුන් විද්‍යාඥයා
විශ්වයේ හමුවන අති ප‍්‍රබල ගුරුත්වයකින් යුත් තමන්ට අසුවන සියල්ල ශූන්‍ය කරන අඳුරු තැන් ලෙස සැලකෙන මේවා කළු කුහර හෙවත් බ්ලැක් හෝල්ස් කියා මුලින් ම හැඳින්වූයේ ජෝන් වීලර් කියන ඇමෙරිකානු භෞතික විද්‍යාඥයායි. ඒ 1967 දී ‘අප දන්නා හා නොදන්නා විශ්වය’ යනුවෙන් දේශනයක් කරද්දීයි. කලින් මේ අපූරු වස්තූන් හැඳින්වූ ‘මිදුණු තරු’ (Frozen stars) ‘අඳුරු තැන්’ (Dark places) ආදී නම්වලට වඩා මෙම නම සිත් ගන්නාසුලූ එකක් වුණු නිසා එදා පටන් ලොව පුරා හැමෝම ‘බ්ලැක් හෝල්’ (Black hole) යන්න භාවිත කරන්න පටන් ගත්තා.

ඔබ හැම දන්නා පරිදි ආලෝකය නිසා තමයි, අපට යමක් පෙනෙන්නේ. යම් වස්තුවක් මතට ආලෝකය පතිත වී පරාවර්තනය වන නිසයි, අපට ඒ වස්තුව දැක ගත හැකි වන්නේ. එසේ ම ආලෝකය විහිදුවන වස්තුත් අපට පෙනෙනවා. කළු කුහර තුළ දී මේ දෙකම සිදුවන්නේ නැහැ. අලෝකය ගිල ගන්නා නිසා විහිදු වීමක්වත් පරාවර්තනය වීමක්වත් සිදු වන්නේ නැහැ. ඒ නිසා ඒවා අපට කෙළින් ම දැක ගන්න විදියක් නැහැ. එහෙනම් කොහොමද විශ්වයේ මේවා ඇති බව දැන ගන්නේ ? දැක ගන්නේ ? යම් හෙයකින් වල්ගා තරුවක් හෝ වාත වලාවක් කළු කුහරයක් මගින් ගිල ගන්නා මොහොතක් කවදා හෝ අපට දැක ගත හැකි වුණොත් එවැන්නක් ස්ථිරව ම ඇති බව සැක හැර දැන ගන්න පුළුවන් වෙයි. ඒත් තවමත් එවැනි තත්වයක් උදා වෙලා නැහැ.

විද්‍යා ප‍්‍රබන්ධ කතාවල එන කළු කුහර
දැනට අපට මේ කළු කුහර වැඩිපුර ම දැක ගත හැක්කේ විද්‍යා ප‍්‍රබන්ධ කතාවලයි. විද්‍යා ප‍්‍රබන්ධ චිත‍්‍රපටයක දී නම් ඔබට මේ කළු කුහරයක් ඇතුළට ගිහින් ත‍්‍රාසජනක අත්දැකීමක් ලබන්නත් පුළුවන්. ඒත් සැබෑවට ම කළු කුහරයක් ඇතුළට ගියොත් ආපසු එන්න ලැබෙන්නේ නැහැ. ඇත්තටම නම් කළු කුහරය යන සංකල්පය න්‍යායාත්මක භෞතික විද්‍යාඥයන්ගේ හිතලූවක්. සැබෑ කළු කුහරයක් ලෙස ස්ථිරව තහවුරු කළ දෙයක් තවමත් සොයා ගෙන නැහැ. 1915 දී ඇල්බට් අයින්ස්ටයින් ඉදිරිපත් කළ ඔහුගේ සාපේක්ෂතා න්‍යාය නිසයි, කළු කුහර පැවතිය හැකි යැයි විද්‍යාඥයන් විශ්වාස කරන්න පටන් ගත්තේ.

අයින්ස්ටයින්ගේ න්‍යායට අනුව ගුරුත්වය අති ප‍්‍රබල වූ විට ආලෝකයේ සියලූ ශක්තිය උරා ගන්නවා, හරියට ග‍්‍රහ ලෝකයක් එහි වායුගෝලය ඇද ගෙන සිර කර ගන්නවා වගේ. ගුරුත්වය ඒ තරම් අති ප‍්‍රබල වෙන්න නම් එහි ඝනත්වය ඉතාමත් දැඩි එකක් වෙන්න ඕනෑ. ඒ කියන්නේ අති දැවැන්ත ස්කන්ධයක් ඉතා කුඩා ඉඩ ප‍්‍රමාණයක් තුළට හැකිළෙන්න ඕනෑ. 1916 දී ජර්මන් තාරකා විද්‍යාඥයකු වූ කාල් ෂ්වෝස්චයිල්ඞ් මේ ගැන ගණනයක් කළා. ඔහු පෙන්නා දුන්නා අපේ සූර්යයා වැනි තරුවක් ආලෝකය උරා ගත හැකි තරමට ඝනත්වයෙන් වැඩි වෙන්න නම් දැනට එහි ඇති විෂ්කම්භය වූ කිලෝ මීටර 1,392,000 ප‍්‍රමාණය කිලෝ මීටර 3ක් තරමට හැකිළෙන්න ඕනෑ.

කළු කුහර හැදන්නේ මෙහෙමයි
1939 ඇමෙරිකානු භෞතික විද්‍යාඥයන් දෙපළක් වන ජේ. රොබට් ඕපෙන්හයිමර් හා හාට්ලන්ඞ් එස්. ස්නයිඩර් විසින් හෙළිදරවු කරනු ලැබුවා, සූර්යයාට වඩා අති විශාල තරු මේ ප‍්‍රමාණයට හැකිළීමට ඉඩ ඇති බව. තරුවක් සිය ජීවිත කාලය පුරා ම එක ම ප‍්‍රමාණයෙන් පවතින්නේ එහි කි‍්‍රයාත්මක වන බලවේගවල සමතුලිත බව නිසයි. තරුවක් තුළ දැවෙන ඉන්ධන ඇති කරන තාපය නිසා තරුව පිටතට ප‍්‍රසාරණය වීමත් ගුරුත්වය නිසා ඇතුළට ඇදීමත් සිදු වෙනවා. කල් යාමේ දී වසර බිලියන ගණනකට පසු මේ තරුවේ න්‍යෂ්ටික ඉන්ධන දැවී අවසන් වීම නිසාත් එහි ඇති අධික බර නිසාත් විනාශ වී යා හැකි බව ඔවුන් පෙන්නා දුන්නා. සූර්යයා මෙන් 3.2ක ගුණයක් වැඩි තරුවක් මේ ආකාරයට විනාශ වී යාම නොවැළක්විය හැකි දෙයකැයි ඔවුන් විසින් ඔප්පු කරනු ලැබුවා. බොහෝ විට කළු කුහර බවට පත් විය හැක්කේ මේ ආකාරයට විනාශ වන අති දැවැන්ත තාරකායි.

විද්‍යාඥයන්ගේ විශ්වාසයට අනුව අප අයත් මන්දාකිණිය වූ ක්ෂීර පථය තුළ පමණක් මෙසේ විනාශ වූ තරුවලින් සෑදුණු කළු කුහර මිලියන 100කට වැඩිය තිබිය හැකි බවයි. 1990 දී නිව් මෙක්සිකෝවේ පිහිටුවා ඇති දැවැන්ත ගුවන්විදුලි දුරේක්ෂකයක් මගින් සොයා ගනු ලැබුවා මේ ක්ෂීර පථය මැද අඛණ්ඩව සිදුවන අති විශාල පිපිරීම් ඇති බව. ඒ පිළිබිඹු අනුව ක්ෂීර පථය මැද අපේ සූර්යයා මෙන් මිලියන හතර ගුණයක් විශාල ස්කන්ධයක් ඇති කළු කුහරයක් තිබිය හැකි යැයි විද්‍යාඥයන් විශ්වාස කරනවා. 1992 දී හබ්ල් අභ්‍යවකාශ දුරේක්ෂය මගින් විද්‍යාඥයන් සොයා ගෙන තියෙනවා, අපේ ක්ෂීරපථය අසල පිහිටි වෙනත් මන්දාකිණියක අපේ හිරු මෙන් මිලියන තුන් ගුණයක් විශාල කළු කුහරයක් ඇති බවට, සලකුණු.

කළු කුහර දැක ගත නොහැකි නිසා විද්‍යාඥයන් ඒවා ඇති තැන් හඳුනා ගන්නට තැත් කරන්නේ ඒවා ඇතැයි සැක කෙරෙන තැන්වල සිදු වන යම් යම් වෙනස්වීම්වලින්. කළු කුහරයක් මැදට කැරකැවෙමින් ඇතුළුවන පදාර්ථවලින් වේගයෙන් විමෝචනය කෙරෙන විකිරණ ගුවන් විදුලි දුරේක්ෂයකින් හසු කර ගන්න පුළුවන්. 1965 දී තාරකා විද්‍යාඥයන්ට සිග්නස් තරු පන්තියෙන් තීව‍්‍ර එක්ස් කිරණ විහිදෙනු දැක ගත හැකි වුණා. ඒ ආලෝක වර්ෂ 10,000ක් ඈතින් පිහිටියක්. 1971 දී ලෝකයේ ප‍්‍රථම එක්ස් කිරණ චන්ද්‍රිකාව මගින් මේ එක්ස් කිරණ ආ දිසාව හරියට ම සොයා ගත්තා. ‘සිග්නස් එක්ස් -1’ කියා නම් කරනු ලැබූ මෙය මුලින් ම හඳුනා ගත් කළු කුහරය ලෙස වාර්තා පොතට එක් වෙනවා. මේ අතින් වාර්තා පොතට එක් වූ අළුත් ම කළු කුහරය වන්නේ 2007 ඔක්තෝබර මුල සතියේ කැලිෆෝනියාවේ සැන්දියේගෝ සරසවියේ ජෙරොමි ඔරෝස් ප‍්‍රමුඛ කණ්ඩායමක් විසින් සොයා ගනු ලැබූ ‘මෙසියර් 33’ නම් මන්දාකිණියේ පිහිටි කළු කුහරයයි. මේ කළු කුහරය අපේ හිරු මෙන් 15.65 ගුණයක් විශාල ස්කන්ධයක් ඇති එකක්. මේ කළු කුහරය වටා අපේ හිරු මෙන් 70 ගුණයක ස්කන්ධයක් තරුවක් ද භ‍්‍රමණය වන බැව් ද මේ විද්‍යාඥයන් සොයා ගෙන තියෙනවා.

විද්‍යාඥයන් හෙළිදරවු කර ඇති ආකාරයට අනුව මෙම කළු කුහර ද අනෙක් තරු හා ග‍්‍රහ වස්තු මෙන් විශ්වය හරහා ගමන් කරනවා. ඒ වගේ ම දැනටමත් කළු කුහර මිලියන ගණනක් විශ්වය තුළ බිහිවී තියෙනවා. එසේ ම විශ්වයේ ඇති යෝධ තරු හැකිළීමෙන් තවතවත් කළු කුහර බිහි වෙනවා. යම් හෙයකින් අපේ සූර්යයා මේ කළු කුහරයක ආකර්ෂණයකට හසු වුවහොත් එය අපේත් අවසානය විය හැකියි. ඒ විතරක් නෙවෙයි අපේ විද්‍යාඥයන් පර්යේෂණාගාර තුළ කුඩාවට කළු කුහර තනන්න උත්සාහ කරනවා. යම් හෙයකින් එවැනි කළු කුහරයක් තනා එය වැරදීමකින් මුදා හරිනු ලැබුවොත් ප‍්‍රමාණය කුඩා වුනත් එවැන්නකටත් අපේ පෘථිවිය ගිල ගැනීමට හැකියාව තියෙනවා.

වාර්තා ගත වූ විශාලතම කළු කුහරය
මෙතෙක් හමුවූ අති දැවැන්තම කළු කුහරය හමුවී ඇත්තේ අපේ අසල්වැසි මන්දාකිණියක් වන මෙසියර් 33 අසලිනි. සර්පිල මන්දාකිණියක් වන මෙම මෙසියර් 33 තුළ පිහිටි මේ කළු කුහරයෙහි ස්කන්ධයේ විශාලත්වය අපේ හිරු මෙන් 15.65 ගුණයක් වෙතැයි සැලකේ. බි‍්‍රතාන්‍යයේ පළ වූ ‘නේචර්’ සඟරාවේ විශේෂ ලිපියක් මගින් මේ බව හෙළි කර ඇත්තේ කැලිෆෝනියාවේ සැන්දියේගෝ සරසවියේ ජෙරොමි ඔරෝස් ප‍්‍රමුඛ කණ්ඩායමක් විසිනි. එසේ ම මෙම කළු කුහරයට ආසන්නව ඒ වටා අපේ හිරු මෙන් 70 ගුණයක ස්කන්ධයක් තරුවක් ද භ‍්‍රමණය වන බැව් ද මේ විද්‍යාඥයන් සොයා ගෙන තිබේ. දින 3.45කට වරක් එම කළු කුහරය වටා යන මෙම තරුව නිසා ආවරණය වන හා නිරාවරණය වන මේ කළු කුහරය නිකුත් කරන එක්ස් කිරණ අධ්‍යයනයෙන් මේ සොයා ගැනීම කිරීමට එම විද්‍යාඥ පිරිස සමත් වී ඇත.

ඔබේ පද්‍ය ගද්‍ය නව නිර්මාණවලට පමණක් නොව......

srishanss — Fri, 23 Dec 2011 13:55:11 +0000

ඔබේ පද්‍ය ගද්‍ය නව නිර්මාණවලට පමණක් නොව පොතපතින් හෝ සමාජයෙන් හෝ ඔබ අත්දුටු දෙයක් වෙතොත් එය අන් අය සමග බෙදා ගැනීමට සුදුසු යැයි හැඟ් නම් ඒවාට ද මෙහි ඉඩ ඇත. ළමයින්ට සුදුසු වැඩිහිටියන්ගේ නිර්මාණ පමණක් නොව ළමා වියේ පසුවන ඔබේ ගද්‍ය පද්‍ය නිර්මාණද ඔබේ නම ගම වයස ලිපිනය ඉගෙන ගන්නා පාසල හා ශ්‍රේණිය සඳහන් කර අප වෙත එවන්න.

Hubble Telescope Spots Complex Organic Molecules on Surface of Pluto

smashb — Thu, 22 Dec 2011 13:18:09 +0000

The Hubble Space Telescope has spotted new evidence of complex organic molecules — the carbon-containing building blocks of life as we know it — on the frigid surface of Pluto, a new study finds.
Hubble observations revealed that some substances on Pluto's surface are absorbing more ultraviolet light than expected. The compounds in question may well be organics, possibly complex hydrocarbons or nitrogen-containing molecules, researchers said.
The dwarf planet Pluto is known to harbor ices of methane, carbon monoxide and nitrogen on its surface. The ultraviolet-absorbing chemical species may have been produced when sunlight or super-speedy subatomic particles known as cosmic rays interacted with these ices, researchers said.

"This is an exciting finding because complex Plutonian hydrocarbons and other molecules that could be responsible for the ultraviolet spectral features we found with Hubble may, among other things, be responsible for giving Pluto its ruddy color," study leader Alan Stern, of the Southwest Research Institute in Boulder, Colo., said in a statement.
Pluto circles the sun in a distant ring of icy bodies known as the Kuiper Belt. Many other Kuiper Belt objects are also quite red, and researchers have previously speculated that organics are responsible for their ruddiness as well.
Stern and his colleagues also found that Pluto's ultraviolet spectrum has changed compared to Hubble measurements taken during the 1990s. They used Hubble's powerful Cosmic Origins Spectrograph instrument to make the find.
These differences may be related to changes in the dwarf planet's terrain since then, researchers said. It's possible that a steep increase in Pluto's atmospheric pressure has caused changes in Pluto's surface, they added.
Overall, the new Hubble observations shed further light on Pluto a few years ahead of the first-ever spacecraft visit to the cold, distant world.
"The discovery we made with Hubble reminds us that even more exciting discoveries about Pluto's composition and surface evolution are likely to be in store when NASA's New Horizons spacecraft arrives at Pluto in 2015," Stern said.
New Horizons launched in January 2006 on a 4-billion-mile (6.4-billion-kilometer) journey to Pluto. The probe is due to make its closest approach to the dwarf planet on July 14, 2015. On that date, New Horizons will be just 7,767 miles (12,500 km) away from the frigid world

Fastest violin player

Asanka — Thu, 24 Nov 2011 02:25:01 +0000

The fastest violinist is David Garrett (Germany) who played "Flight of the Bumblebee" in 1 min 5.26 sec on the set of Guinness World Records: Die GroBten Weltrekorde in Germany, on 20 December 2008.

“Only those artists can afford to do crossover who have already made a name for themselves in the classical music scene.” David Garrett sets high quality standards. And he knows what he is talking about. In Fall 2007 the recording artist made his appearance in Germany with the release of his crossover album Virtuoso and he has been redefining standards in the classic and crossover scene step by step ever since. The native of Aachen, son of a German jurist and an American prima ballerina, can allow himself to sound out the limits. After all, at age 30, he already looks back on a matchless career.

Race to Mine the Moon Heats Up

thisaraprabudda — Tue, 01 Nov 2011 15:36:54 +0000

Moon, we just can’t quit you.

NASA has shifted its goals from returning to the moon to visiting an asteroid or even Mars, but not everyone has given up on going back. The space agency's attention deficit has sparked a race among private companies eager to return to Earth's satellite.

The latest competitor is Astrobotic Technology, a spinoff of the Robotics Institute at Carnegie Mellon University. Its goal: to mine the moon for water and fuel. And a deal with NASA plus a contract for rides on private rockets means the company may be the first to go back.
“We are in the first three months of a two-year contract,” David Gump, president of Astrobotic, told FoxNews.com. "We'll have a field-tested robot that will be able to go to the poles" on the moon to extract water, methane and more, he said.

Astrobotic isn't the only company that hopes to dig up the moon. Last week, FoxNews.com revealed the story of Moon Express, which sees greenbacks in all that lunar "green cheese." In all, 26 companies are in the race, many fueled by the Google Lunar X Prize, a $20 million contract to put men back on the moon.

But a contract with the California company SpaceX to hitch a ride to the moon on its Falcon 9 rockets sets Astrobotic apart, the company argues. On board the rocket, which is planned to launch in late 2014 or early 2015, will be Astrobotic’s own lunar lander, which will take the company’s mining robot to the moon’s surface.

SpaceX spokeswoman Kirstin Brost Grantham confirmed to FoxNews.com that the contract does in fact exist.

Even NASA has a stake in the company, having negotiated seven contracts with Astrobotic, the company claims: one to develop an excavator and others to give NASA information on how the company will carry out its mission at a low cost.

Potential targets include water, methane, and ammonia, hidden in pockets within the moon. Scientists are certain these elements exist beneath the lunar surface, but are unsure about the quantities and in what form they reside.

“The readings ... indicate there’s pretty substantial water at the poles, but we won’t know more until you go and take samples,” Gump told FoxNews.com. “So we’ll both confirm the readings taken from orbit and discover how the resource is spread out.”

While the company’s main focus is to extract these substances from the poles, Astrobotic hopes to find an even rarer element on the moon, one that could have a potentially huge impact on life on Earth the mysterious helium 3.

“There’s an element deposited by the solar wind called helium 3 that many people believe is the key element for fusion reactors,” Gump said.

Current nuclear reactors work through fission, which involves radioactive fuel and generates large quantities of heat. “If we can convert to a fusion fuel cycle, it’s carbon free and radiation free,” Gump said. “It could really improve things on Earth and be the basis for a very benign and cost-effective way to stabilize our civilization.”

Astrobotic's dreams reach beyond lunar excavation. The company has corporate sponsorships in return for delivering large payloads of roughly 240 pounds to the moon, including scientific instruments that need testing on the lunar surface. Only 15 percent of the company's revenues will come from the Google Lunar X Prize, Gump claims. Contracts are the real treasures.

Trackmania 2-Canyon

ruwaiz — Mon, 12 Sep 2011 17:27:27 +0000

developer: Nadeo
publisher: Ubisoft
genre: wyœcigi i rajdy / cars
platform: PC / Windows

release date: World: 14 September 2011
USA: 14 September 2011
Europe: 14 September 2011
play modes: single / multiplayer
multiplayer: LAN / Internet
game language: English
age requirements: everyone
suggested system requirements:
Core 2 Duo 1.5 GHz, 1 GB RAM (2 GB RAM - Vista/7), graphic card 256 MB (GeForce 6800 or better), 1.5 GB HDD, Windows XP/Vista/7.

2012 BMW Z4 sDrive28i

fehanmr — Tue, 09 Aug 2011 15:29:10 +0000

BMW's Turbo Four-cylinder Z4 - 2011 New York Auto Show

One of the big reveals at the 2011 New York International Auto Show wasn't a car but an engine. KBB's Micah Muzio spoke with Joseph Wierda from BMW to discuss the company's new turbocharged four-cylinder Z4.

Ion-powered Dawn begins study of asteroid Vesta

chinthaka5 — Wed, 03 Aug 2011 07:19:55 +0000

Four years after launch from Cape Canaveral, NASA's ion-drive Dawn spacecraft is finally in orbit around the asteroid Vesta, studying the second largest body in the rubble-strewn belt between Mars and Jupiter in unprecedented detail. Pictures released today show a strangely tortured world with huge parallel grooves separating the heavily cratered northern hemisphere from smoother terrain in the south dominated by the chaotic remnants of a catastrophic impact.
"These photos have been already a great revelation to the team about what the surface is like," Christopher Russell, the mission's principal investigator, told reporters today. "We did not imagine the detail we're seeing and the various processes that we're seeing evidence of now. These are really insightful into this building block of the early solar system...It's really a beautiful and exciting small world sitting there in the middle of the asteroid belt that we're going to learn very much about."

Discovered in 1807, Vesta is roughly spherical, measuring about 359 miles by 285 miles. It is the largest member of the asteroid belt yet visited by a robotic spacecraft, second in size only to Ceres, Dawn's next target and, along with Pluto, one of just five known dwarf planets. NASA is spending $466 million to explore Vesta and Ceres during the course of a 10-year mission.
Vesta's surface is believed to be made up of basaltic rock that flowed out of a presumably hot interior when the asteroid formed some 4.5 billion years ago. Because of its small size, the asteroid presumably cooled quickly and did not undergo subsequent resurfacing like larger worlds.
As such, Vesta may have one of the oldest, most pristine surfaces in the solar system, a frozen snapshot of the materials and conditions that existed at the dawn of the solar system.
"We believe this goes back to the first 5 million years of the solar system," Russell said. "What happened back then was that the material that was orbiting what was going to become the sun began to condense. We have evidence of what was going on through very primitive meteorites that have fallen to the Earth.
"Right when Vesta started to come together, we believe there was a supernova that irradiated the material and added radioactive material to it that when the material came together, it had an additional heat source and some of these bodies that were formed melted and then differentiated, they made a crust of lava and an iron core. Those are some of the oldest bodies out there."
Earlier observations by the Hubble Space Telescope showed what appeared to be a titanic impact crater near Vesta's south pole that stretches some 285 miles across and measures some eight miles deep. More than 200,000 cubic miles of debris were blasted into space, according to the Dawn press kit, some of which eventually made its way to Earth as meteorites.
To put the impact into perspective, a proportionately sized crater on Earth would be roughly the size of the Pacific Ocean.
Images from Dawn show chaotic terrain near the south pole dominated by a towering central peak and huge ripple-like grooves stretching around the asteroid's equator. Terrain north of the grooves is much more heavily cratered.

"Those grooves are pretty much in the equatorial region and they're very much perpendicular to the direction we think the impact was going when it struck Vesta," Russell said. "So one thing it could be is that when the compression of that fantastic impact came, Vesta got smaller in that direction for a while and then expanded and that caused tectonic features around the equatorial region."
Launched atop a United Launch Alliance Delta 2 rocket on September 27, 2007, Dawn is the first operational deep space mission to be equipped with an ion propulsion system. Instead of burning liquid propellants in short, high-power bursts, Dawn's propulsion system works by using electrical power to ionize and accelerate electrically charged xenon to velocities 10 times greater than the exhaust from chemical rockets.
Dawn's ion propulsion system "only pushes on the spacecraft as hard as this single piece of paper pushes on my hand," said Marc Rayman, mission manager and chief engineer, holding up a single piece of paper. "And yet gradually, over time, the effect of this whisper-like thrust can build up and produce fantastically high velocity. So this is what I like to call acceleration with patience. And now, our patience is paying off very handsomely indeed."
During final approach to Vesta, Dawn's closing velocity was just 60 miles per hour relative to the asteroid. Finally, on July 15, the spacecraft was captured by Vesta's weak gravity, putting it in orbit.
"Thanks to all the thrusting we've been doing all along the way, Dawn was able to slowly creep up on Vesta and slip ever so gently into orbit with the same grace and elegance it's displayed in nearly a thousand days of inner planetary ion thrusting," Rayman said.
Dawn's initial orbit around Vesta carries it over the asteroid's poles at an altitude of roughly 1,700 miles. The orbit's orientation keeps the spacecraft and its huge solar panels in direct sunlight to provide power for its instruments and its propulsion system.
Traveling from north to south, Dawn will complete one orbit every three Earth days. Because Vesta completes one rotation or "day," every five hours and 20 minutes, Dawn will be able to observe the asteroid's entire illuminated surface every orbit. During south-to-north passes above Vesta's night side, Dawn will transmit stored images and other data back to Earth

Operating in the initially high survey orbit, Dawn's instruments will provide a global view of Vesta in ultraviolet, visible and infrared wavelengths. A mapping spectrometer will observe the surface with a resolution of 2,300 feet per pixel while the spacecraft's visible-light cameras will resolve features as small as 820 feet across, about 150 times better than images taken by the Hubble Space Telescope.
Dawn's gamma ray and neutron detector will help researchers characterize the surface composition of Vesta while analysis of subtle changes in the spacecraft's radio signal, caused by slight changes in Dawn's orbital velocity, will help scientists map out the asteroids gravity field and internal structure.
After seven orbits, or about three weeks in the survey orbit, Dawn's ion propulsion system will spend a month or so slowly lowering the orbit to an altitude of about 420 miles, allowing the spacecraft to circle the asteroid twice each Earth day.
Dawn will complete about 60 trips around Vesta in this so-called high-altitude mapping orbit, or HAMO, surveying the asteroid in extraordinary detail, allowing scientists to build topographic maps showing the elevation of hills and mountains and the depths of the craters dotting its surface.
After HAMO operations are complete, Dawn will spend about six weeks dropping down to a low-altitude mapping orbit, or LAMO, at less than 110 miles, circling Vesta every four hours.
While the lower orbit will give Dawn's cameras sharp views of Vesta's surface, the primary goal of this 10-week phase of the mission is to allow the gamma ray and neutron detector to monitor cosmic ray impacts on the surface. High-energy cosmic rays hitting atoms in the upper three feet of the surface will release gamma rays and neutrons that can be used to determine the identities of the original atoms.
The effects of Vesta's gravity on Dawn's orbit will be more pronounced in the low-altitude orbit, allowing scientists to map out its internal mass distribution.
When the low-altitude phase of the mission is complete, Dawn will spend another six weeks spiraling out for a second set of observations at an altitude of 420 miles, identical to the earlier high-altitude mapping orbit. Because about eight months will have passed between the two sets of observations, more of Vesta's northern hemisphere will be illuminated as the asteroid's seasons progress and areas not seen earlier will be mapped at the same level of detail.
If all goes well, Dawn will begin its departure from Vesta in June 2012, setting off on a two-and-a-half-year voyage to Ceres. The mission is funded through July 2015.

Skype Pulls Premature iPad App

shash — Wed, 03 Aug 2011 06:38:23 +0000

Skype said Tuesday that it removed its new iPad app from Apple's App Store, saying that the program was posted prematurely.
"To ensure your best Skype experience, we've temporarily removed Skype for iPad which went live prematurely today [Tuesday]," the company said on its Twitter account. "We know you've been eagerly awaiting Skype for iPad and apologize for the inconvenience."
The program reportedly allowed audio and video calling over both 3G and Wi-Fi networks.
Skype is in the process of being acquired by Microsoft.

20-Million Year-Old Ape Skull Found in Uganda

shan_ali — Wed, 03 Aug 2011 06:35:46 +0000

Ugandan and French scientists have discovered a fossil of a skull of a tree-climbing ape from about 20 million years ago in Uganda's Karamoja region, the team said Tuesday.
The scientists discovered the remains on July 18 while looking for fossils in the remnants of an extinct volcano in Karamoja, a semi-arid region in Uganda's northeastern corner.
"This is the first time that the complete skull of an ape of this age has been found. It is a highly important fossil," Martin Pickford, a paleontologist from the College de France in Paris, told a news conference.
Pickford said preliminary studies of the fossil showed that the tree-climbing herbivore, roughly 10-years-old when it died, had a head the size of a chimpanzee's but a brain the size of a baboon's, a bigger ape.
Bridgette Senut, a professor at the Musee National d'Histoire Naturelle, said that the remains would be taken to Paris to be x-rayed and documented before being returned to Uganda.
"It will be cleaned in France, it will be prepared in France and then in about one year's time it will be returned to the country," Senut said.
Uganda's junior minister for tourism, wildlife and heritage said the skull was a remote cousin of the Hominidea Fossil Ape.

Mummy Smugglers Reveal Vast Antiquities Black Market

aahil — Thu, 28 Jul 2011 06:20:01 +0000

The rescue of an ancient Egyptian mummy's sarcophagus this month from alleged smugglers in New York — the first time authorities say an international artifacts' smuggling ring was dismantled within the United States — sounds more like the plot of a movie than reality.

Amazingly, however, mummy smuggling not only still happens today, it was once so common that enough mummies were available to be ground up and sold as powder, archaeologists reveal.

"Mummy powder was something you could buy in pharmacies up to 1920, because people thought it was a type of medication," said Egyptologist Regine Schulz, curator of ancient art at the Walters Art Museum in Baltimore.

Today's black market for mummy and other antiquities is in the billions of dollars, though exact numbers aren't known. Besides not having a clear bead on the breadth of trafficking in Egyptian artifacts, scientists and officials say it's often difficult to protect the precious artifacts as the Egyptian desert is so vast. [Science as Art: A Gallery]

A long history of mummy dealings

The trafficking of mummies traces back to medieval times.

"When Christianity and Islam were rising, mummification was not really the main habit anymore, although we have some mummies of Christian bishops in Egypt that do date back to the seventh and eighth centuries A.D.," Schulz said. "So from the Middle Ages on, mummies were a bit curious and strange."

Nevertheless, so many mummies were made during ancient Egypt times that enough were available to make mummy powder, or mummia, whose pigment "one assumes was a dark brown," said Gary Vikan, director of the Walters Art Museum.

"Mummification was not just something for pharaohs or the upper class — it was the normal thing in ancient Egypt for hundreds of years," Schulz said. "My aunt lived for many years in Egypt in the 1950s and 1960s, and sandstorms would often reveal tiny remains of mummies — sometimes a little wrapping, sometimes a little bone." [Top 10 Weird Ways We Deal With the Dead]

Given the way mummification helped preserve the body, people thought mummies had something to do with eternity, and, in turn that mummy powder could be used as medication, Schulz said.

As strange as grinding up ancient corpses for sale might be in modern times, "mummies were seen as objects back then, not people," Schulz said. "There was nothing illegal about it."

Nowadays, smuggling mummies and any other antiquities out of Egypt is strictly against the law.

"People began to say, 'Wait a moment, this is a person that should be treated in a respectful way, not a thing,'" Schulz said.

Still, while traffic in mummies and Egyptian antiquities has fallen, a black market for them still exists, and the recent upheaval in Egypt may have made it easier for criminals to loot the country.

Modern crime

In the latest news in this front, on July 13 federal prosecutors announced they had busted an international antiquities smuggling ring, charging antiquities dealers in New York, Michigan and Dubai with conspiring with a collector in Virginia to smuggle Egyptian artifacts into the United States and launder money to further their crimes. The prizes in question include a Greco-Roman style Egyptian sarcophagus, a nesting set of three Egyptian sarcophagi, a set of Egyptian funerary boats and Egyptian limestone figures, a collection with an estimated market value of $2.5 million.

"This is a groundbreaking case for Homeland Security Investigations — it is the first time an alleged cultural property network has been dismantled within the United States," said James Hayes, special agent-in-charge with U.S. Immigration and Customs Enforcement and Homeland Security Investigations. "In addition to smuggling cultural property, this case also focuses on significant money-laundering activity. This is notable because the illicit sale of cultural property is the third most profitable black market industry following narcotics and weapons trafficking."

The specific numbers regarding art crime remain vague at best, due to the dearth of accurate statistics regarding it, but estimates have suggested it brings in $2 billion to $6 billion annually.

There is no doubt an illegal market for mummies — "people are still interested in buying them," Schulz said. "But people are more interested in their coffins or maybe a nest of coffins, in what is around the mummy. The mummy itself is not the highest priority."

A great deal remains unknown as to how much gets smuggled or what even gets stolen. The International Council of Museums is preparing a red list for Egypt — a catalog of archaeological objects and works of art in danger of getting stolen or sold. Still, in places in Egypt where families are poor and foreigners are offering a great deal of money, "it's not surprising if there are people who excavate and sell things even if it is illegal," Schulz said.

At the same time, the vast nature of the desert in Egypt makes it impossible to defend every possible site from looters.

There remains much scientists can learn about the past using mummies, even without unwrapping them. "We can now X-ray them to find out how old they were, what illnesses they had, what they ate and what might be inside the wrappings. We can learn a lot about the ancient Egyptians and also the individuals. If you are illegally dealing in mummies and looting tombs, you're destroying what we can learn."

Bird or Dinosaur? Famous Fossil Not First Bird After All

nalakadas — Thu, 28 Jul 2011 06:13:44 +0000

One of the world's most famous fossil creatures, widely considered the earliest known bird, is getting a rude present on the 150th birthday of its discovery: A new analysis suggests it isn't a bird at all.

Chinese scientists are proposing a change to the evolutionary family tree that boots Archaeopteryx off the "bird" branch and onto a closely related branch of birdlike dinosaurs.

Archaeopteryx (ahr-kee-AHP'-teh-rihx) was a crow-sized creature that lived about 150 million years ago. It had wings and feathers, but also quite un-birdlike traits like teeth and a bony tail. Discovered in 1861 in Germany, two years after Charles Darwin published "On the Origin of Species," it quickly became an icon for evolution and has remained popular since.

The Chinese scientists acknowledge they have only weak evidence to support their proposal, which hinges on including a newly recognized dinosaur.

Other experts say the change could easily be reversed by further discoveries. And while it might shake scientific understanding within the bird lineage, they said, it doesn't make much difference for some other evolutionary questions.

Archaeopteryx dwells in a section of the family tree that's been reshuffled repeatedly over the past 15 or 20 years and still remains murky. It contains the small, two-legged dinosaurs that took the first steps toward flight. Fossil discoveries have blurred the distinction between dinosaurlike birds and birdlike dinosaurs, with traits such as feathers and wishbones no longer seen as reliable guides.

"Birds have been so embedded within this group of small dinosaurs ... it's very difficult to tell who is who," said Lawrence Witmer of Ohio University, who studies early bird evolution but didn't participate in the new study.

The proposed reclassification of Archaeopteryx wouldn't change the idea that birds arose from this part of the tree, he said, but it could make scientists reevaluate what they think about evolution within the bird lineage itself.

"Much of what we've known about the early evolution of birds has in a sense been filtered through Archaeopteryx," Witmer said. "Archaeopteryx has been the touchstone... (Now) the centerpiece for many of those hypotheses may or may not be part of that lineage."

The new analysis is presented in Thursday's issue of the journal Nature by Xing Xu of the Chinese Academy of Sciences in Beijing, and colleagues. They compared 384 specific anatomical traits of 89 species to figure out how the animals were related. The result was a tree that grouped Archaeopteryx with deinonychosaurs, two-legged meat-eaters that are evolutionary cousins to birds.

But that result appeared only when the analysis included a previously unknown dinosaur that's similar to Archaeopteryx, which the researchers dubbed Xiaotingia zhengi. It was about the size of a chicken when it lived some 160 million years ago in the Liaoning province of China, home to many feathered dinosaurs and early birds.

Julia Clarke of the University of Texas at Austin, who did not participate in the study, said the reclassification appeared to be justified by the current data. But she emphasized the study dealt with a poorly understood section of the evolutionary tree, and that more fossil discoveries could very well shift Archaeopteryx back to the "bird" branch.

Anyway, moving it "a couple of branches" isn't a huge change, and whether it's considered a bird or not is mostly a semantic issue that doesn't greatly affect larger questions about the origin of flight, she said.

Luis Chiappe, an expert in early bird evolution at the Natural History Museum of Los Angeles County who wasn't part of the new study, said he doesn't think the evidence is very solid.

Ancient Egyptian Royalty Wielded Serious Weapons

sriflag — Tue, 26 Jul 2011 05:57:17 +0000

Elite members of ancient Egypt, including the pharaoh himself, likely wielded ornate daggers, swords and axes in battle, or to personally execute prisoners, rather than using the shiny metal for ceremonial purposes, research suggests.

The weapons were used during the Bronze Age, a period between 5,000 and 3,000 years ago when the civilization was at its height, according to Daniel Boatright, an Egyptologist at Isle of Wight College in the United Kingdom.

This finding is "strange considering the amount of literature that's been composed so far that basically says that all of them were for ritualistic purposes and were never used in battle," Boatright told LiveScience.

Royalty are known to have gone into battle. For instance, Prince Andrew, during the Falklands War, and Prince Harry, in Afghanistan, have served with British troops. "I can't see any reason why they wouldn't four or five thousand years ago as well," he said. [The History of Human Aggression]

Boatright did caution that it can't be ruled out that the weapons may have been used for animal sacrifices.

Subtle evidence

Boatright analyzed 125 Bronze Age weapons from Egypt, including daggers, swords, arrowheads, axes and spears. He also reviewed reports on 350 additional weapons from that period.

Many of the artifacts had been robbed from tombs and archaeological sites more than 100 years ago, and were eventually acquired by museums or collectors in the 19th or early 20th century. [Thousands of Tombs from Saudi Desert Spotted from Space]

"There's very little evidence to suggest that they would [belong to] people who were necessarily the average citizen," he said. "A couple of them actually have been linked to tombs in the Theban acropolis, so linked to the Valley of the Kings."

He used microscopy and other lab analyses to look for evidence of how the weapons were used.

"The funny thing about this whole process was that most of them seem to actually have the capacity to be used. There are very, very few that seem to have any ornamental or purely ritualistic context," Boatright said.

Not only were they able to be used in battle, it seems about half of the 125 weapons studied showed evidence of wear and tear, suggesting they were actually used. Some of them, such as an ax with a dent in it, are obvious, while others are more subtle, like small nicks on the edge of a blade.

The evidence suggests that elite members of Egyptian society may have gone into battle or executed prisoners personally. "I think there's an argument for it. Whether they were actually in the middle of the battle, or standing to one side, remains to be seen," Boatright said.

A pharaoh's revenge?

One interesting artifact he studied was a bronze dagger that archaeologists believe may have belonged to Kamose. It was possibly used to avenge the death of his father, Pharaoh Seqenenre Tao II.

The mummy was discovered by Egyptologist Gaston Maspero in 1886. Upon unwrapping the mummy, he found that the king had died from multiple ax wounds.

"It is not known whether he fell upon the field of battle or was the victim of some plot; the appearance of his mummy proves that he died a violent death when about 40 years of age. Two or three men, whether assassins or soldiers, must have surrounded and despatched him before help was available," Maspero wrote in volume four of his 1901 book, "History of Egypt, Chaldea, Syria, Babylonia and Assyria" (Optal eBooks, 2009).

Seqenenre Tao II lived 3,500 years ago, at a time when much of Egypt was controlled by the Hyksos, a people from Asia who ultimately killed Tao. The dead king's son Kamose took up his cause, campaigning against them.

"It's quite a long dagger, actually it borderlines on a sword," Boatright said. Upon examining it, Boatright found groove marks on the blade and tiny nicks on its edge, evidence suggesting the weapon was used.

"It could be something that's been used by Kamose to attack someone, or something used on a daily basis."

Given the violence of the period Kamose lived in, Boatright believes it is possible that Kamose used the dagger against another person, possibly to avenge the death of his father.

"It easily could have been, bearing in mind the state his father was found in; Seqenenre Tao, his body was totally and utterly bashed into a pulp before he died," Boatright said.

The research was presented last year at the third annual British Egyptology Congress at University College London. An article was also published at the same time in the journal Archaeological Review from Cambridge.

Ancient Dino-Eating Croc Had Huge Teeth, Dog Face

nuwan600 — Tue, 26 Jul 2011 05:54:11 +0000

A crocodilian fossil with big teeth and a doglike skull is now shedding light on the anatomy of a strange group of predators, scientists have revealed.

The fossil was unearthed by a municipal worker in a small town in Minas Gerais, Brazil. It dates back 70 million years, near the end of the Age of Dinosaurs.

"Whereas modern-day amphibious crocodiles have low and flat heads, this new find gives us one of the first detailed insights into the head anatomy of this weird group of extinct crocs called Baurusuchia that feature tall, doglike skulls with enlarged canines, and long-limbed body proportions," said researcher Hans Larsson at McGill University in Canada. [Pictures of Monster Reptiles]

The creature is named Pissarrachampsa sera. Pissarrachampsa means "a crocodile from piçarra," the local name for fossil-bearing sandstones, and sera means "late," referring to how it was one of the last fossils found during the 2008 expedition that uncovered it. It also refers to the local flag that quotes Virgil — "Libertas Quae Sera Tamen" — meaning "Freedom, Albeit Late."

This croc almost certainly did not lurk like a log in a river like its modern relatives. "The rocks from the outcrop where we found the fossils, as well as those from other related areas, suggest a hot and considerably dry environment for the region dating back 70 million years," researcher Felipe Montefeltro, a paleontologist at the University of Sao Paulo in Brazil, told LiveScience.

Instead, the ecology of the predators was probably similar to that of wild dogs living today, researchers said. Given the number and size of their teeth, the crocs probably fed on animals of about the same 15- to 20-foot (4.5 to 6 meter) size, including dinosaurs and fellow crocs from the region, the researchers say. Rather than clambering over the ground like the crocs we see today, P. sera would have galloped on long limbs.

Similar to other crocodilians of its era, this croc had plated armor, roughened bone surfaces and massive attachments for jaw-closing muscles. Still, the baurusuchid lineage of crocodilians this new fossil belongs to is known for many unique anatomical features, such as unusually large canine teeth, forward-facing nostrils and tall, thin skulls.

"We are dealing with an exceptionally divergent lineage of extinct crocodile diversity," Montefeltro said. "There are many fossils that still need to be found to link this crocodile to those who came before and after."

A digital reconstruction of the fossil's brain cavity is in the works and is revealing information on the creature's brain size and shape, and hearing abilities. Those results will be presented in the fall at the Society of Vertebrate Paleontology's annual meeting. The researchers will also look at the rest of P. sera's internal structures in detail "to find clues about how this crocodile lived and why it is so peculiar," Montefeltro said.

Found: Ancient Peruvian Executioner's Lost Head

GrejeshGajan — Thu, 21 Jul 2011 07:10:13 +0000

Archaeologists in Peru have discovered the tomb of a lord of the Lambayeque culture, believed to have been an executioner due to the three ceremonial knives found buried with him.
Near the pre-Hispanic tomb were human remains, as well as ceremonial knives, ceramic pots, a dress made from native cotton and a series of rolled copper discs, said Carlos Wester, director of the Bruning Museum in Lambayeque and one of the tomb's discoverers.
Wester told AFP the person buried there was most likely in charge of human sacrifice.
"We found the perfectly preserved tomb of a sacrificer of the Lambayeque culture, with copper machetes and human offerings laid around them," Wester told the news agency.
The tomb was found in a place called "ceremonial fertility and water," two weeks ago in the archaeological complex Chotuna Chornancap, a thousand-year-old temple complex discovered in January 2010.
The 20 to 30 year old resident of the tomb "played an important role in the ceremonies of human sacrifice" for the ancient culture, which flourished from 700 to 1375 AD. Sicán or Lambayeque culture emerged around the eighth century, lasted until 1375 and peaked between 900 and 1100.
This civilization worshiped the "Lord of Sican"; during the heyday of the culture, there were seven to eight such figures representing the heavenly power on earth.
They were described as wearing masks with winged eyes and pointed ears, the archaeologist said.