Senin, 11 April 2011

Yuri Gargarin

Yuri Gagarin
Yuri Gagarin
Credits - NASA
“Man Enters Space” headline
Credits - NASA

Colonel Yuri A. Gagarin, popularly called “The Columbus of the Cosmos,” was born on a collective farm in a region west of Moscow, Russia, on March 9, 1934. His father was a carpenter. Yuri attended the local school for six years and continued his education at vocational and technical schools.

Yuri Gagarin joined the Russian Air Force in 1955 and graduated with honors from the Soviet Air Force Academy in 1957. Soon afterward, he became a military fighter pilot. By 1959, he had been selected for cosmonaut training as part of the first group of USSR cosmonauts.

Yuri Gagarin flew only one space mission. On April 12, 1961 he became the first human to orbit Earth. Gagarin's spacecraft, Vostok 1, circled Earth at a speed of 27,400 kilometers per hour. The flight lasted 108 minutes. At its highest point, Gagarin was about 200 miles (327 kilometers) above Earth.

Once in orbit, Yuri Gagarin had no control over his spacecraft. Vostok's reentry was controlled by a computer program sending radio commands to the space capsule. Although the controls were locked, a key had been placed in a sealed envelope in case an emergency situation made it necessary for Gagarin to take control. As was planned, Cosmonaut Gagarin ejected after reentry into Earth's atmosphere at an altitude of 20,000 feet and landed by parachute. As pilot of the spaceship Vostok 1, he proved that man could endure the rigors of lift-off, re-entry, and weightlessness.

As a result of his historic flight he became an international hero and legend. Colonel Gagarin died on March 27, 1968 when the MiG-15 airplane he was piloting crashed near Moscow. He was given a hero's funeral, his ashes interred in the Kremlin Wall. At the time of his death, he was in training for a second space mission.

Yuri Gagarin: First Man in Space

Yuri Gagarin becomes the first man in space on April 12, 1961 
April 12 was already a huge day in space history twenty years before the launch of the first shuttle mission. On that day in 1961, Russian cosmonaut Yuri Gagarin (left, on the way to the launch pad) became the first human in space, making a 108-minute orbital flight in his Vostok 1 spacecraft. Newspapers like The Huntsville Times (right) trumpeted Gagarin's accomplishment.

Mercury astronaut Alan Shepard became the first American in space less than a month later.

Scientific cooperation with the Soviet Union dates back to the very beginnings of space flight. The first cooperative human space flight project between the United States and the Soviet Union took place in 1975. The Apollo-Soyuz Test Project was designed to test the compatibility of rendezvous and docking systems for American and Soviet spacecraft and to open the way for future joint manned flights.

Since 1993, the U.S. and Russia have worked together on a number of other space flight projects. The Space Shuttle began visiting the Russian Mir space station in 1994, and in 1995 Norm Thagard became the first U.S. astronaut to take up residency on Mir. Seven U.S. astronauts served with their Russian counterparts aboard the orbiting Mir laboratory from 1995 to 1998. The experience gained from the Mir cooperative effort, as well as lessons learned, paved the way for the International Space Station.

In-orbit construction on the Station began in November 1998, and it has been staffed non-stop with international crews since November 2000. The first Station crew, made up of U.S. commander Bill Shepherd and cosmonauts Yuri Gidzenko and Sergei Krikalev, was launched on board a Russian Soyuz spacecraft. The crew returned to Earth on the Space Shuttle Discovery in March 2001.

49 Tahun Setelah Yuri Gagarin Mengangkasa

Tonggak sejarah perjalanan manusia ke ruang angkasa diawali pada 12 April 1961.

Kosmonot Uni Soviet, Yuri Gagarin, yang saat itu baru berusia 27 tahun, mencatatkan diri sebagai manusia pertama yang terbang ke luar angkasa.

Dengan pesawat luar angkasa Vostok 1, Yuri Gagarin berada di orbit Bumi selama 108 menit. Sebuah perjalanan yang mengubah sejarah manusia. Prestasi inilah yang kemudian membuat Presiden AS JF Kenedy, terobsesi untuk mendaratkan astronot AS di Bulan.

Namun, Yuri Gagarin tak lama menikmati status tenarnya sebagai manusia pertama di luar angkasa. Gagarin meninggal pada tanggal 27 Maret 1968, ketika pesawat MiG-15 yang dia piloti jatuh di dekat Moskow.

Kini, 49 tahun perjalanan Yuri Gagarin menembus langit bukan hanya diaku sebagai bagian sejarah Uni Soviet yang telah pecah, namun sejarah dunia.

Pada 12 April 2010, perayaan memperingati jejak sejarah Yuri Gagarin tak hanya dilangsungkan di berbagai negara di dunia, dari New York , Washington DC, Los Angeles, London, Tokyo, Moskow, Sydney, Beijing, Delhi, hingga Nairobi.

"Hari Yuri Gagarin' bahkan diperingati di luar angkasa.
Presiden Rusia Dmitry Medvedev meminta para penghuni Stasiun Antariksa Internasional yang terdiri dari tiga kosmonot Rusia, dua astronot Amerika dan satu astronot Jepang memperingati dua tonggak penting dalam perjalanan ruang angkasa.
Selain mengingat perjalanan Yuri Gagarin, di hari yang sama, juga diperingati 29 tahun peluncuran pesawat ulang alik pertama.
"Ruang angkasa adalah sesuatu yang menyatukan kita semua. Ini adalah isu global, " kata Medvedev pada para astronot dan kosmonot, seperti dimuat laman The Globe and Mail.

Tiga hari kemudian, Presiden Amerika Serikat, Barack Obama menyuarakan mimpi fantastis misi luar angkasa Amerika Serikat.

Sama dengan langkah John F Kennedy pada 1961 yang bercita-cita mengirim astronot ke Bulan -- yang berhasil diwujudkan pada 1969, Obama ingin membuat terobosan baru.

Pada 2025, AS akan memiliki pesawat luar angkasa baru yang dirancang untuk perjalanan jarak jauh.

Juga, misi luar angkasa yang melampaui Bulan -- ada orang-orang terpilih yang akan menjelajah belantara ruang angkasa.

"Kita akan memulai dengan mengirim astronot ke asteroid untuk kali pertamanya dalam sejarah," kata Obama, seperti dimuat laman Daily News, Jumat 16 April 2010.

"Pertengahan tahun 2030-an, saya yakin kita akan bisa mengirim manusia ke orbit Mars dan mengembalikan mereka dengan selamat ke Bumi," kata Obama.

"Selanjutnya, kita akan mengirim manusia pertama yang akan menginjakkan kaki di Mars. Saya harap ada di sana untuk menyaksikannya," kata Obama, optimistis.

Jumat, 08 April 2011

WISE Up: Space Photos from NASA's Sky-Mapping Telescope

Hidden Galaxy Photographed by Peeping Space Telescope
Hidden Galaxy Photographed by Peeping Space TelescopeCredit: NASA/JPL-Caltech/UCLAA leggy cosmic creature, actually the "hiding galaxy" IC 342, comes out of hiding in this new infrared view from NASA's Wide-field Infrared Survey Explorer, or WISE.

Meet Mimas: Saturn's Death Star Moon


The Expanding Universe: From the Big Bang to Today

The universe was born with the Big Bang as an unimaginably hot, dense point. When the universe was just 10-34 of a second or so old — that is, a hundredth of a billionth of a trillionth of a trillionth of a second in age — it experienced an incredible burst of expansion known as inflation, in which space itself expanded faster than the speed of light. During this period, the universe doubled in size at least 90 times, going from subatomic-sized to golf-ball-sized almost instantaneously.
After inflation, the growth of the universe continued, but at a slower rate. As space expanded, the universe cooled and matter formed. One second after the Big Bang, the universe was filled with neutrons, protons, electrons, anti-electrons, photons and neutrinos.
During the first three minutes of the universe, the light elements were born during a process known as Big Bang nucleosynthesis. Temperatures cooled from 10^32 degrees K to 10^9 degrees K, and protons and neutrons collided to make deuterium, an isotope of hydrogen. Most of the deuterium combined to make helium, and trace amounts of lithium were also generated.
For the first 380,000 years or so, the universe was essentially too hot for light to shine. The heat of creation smashed atoms together with enough force to break them up into a dense plasma, an opaque soup of protons, neutrons and electrons that scattered light like fog.
The globular cluster NGC 6397 contains around 400,000 stars and is located about 7,200 light years away in the southern constellation Ara. With an estimated age of 13.5 billion years, it is likely among the first objects of the Galaxy to form after the Bi

Roughly 380,000 years after the Big Bang, matter cooled enough for atoms to form during the era of recombination, resulting in a transparent, electrically neutral gas. This set loose the initial flash of light created during the Big Bang, which is detectable today as cosmic microwave background radiation. However, after this point, the universe was plunged into darkness, since no stars or any other bright objects had formed yet.
About 400 million years after the Big Bang, the universe began to emerge from the cosmic dark ages during the epoch of reionization. During this time, which lasted more than a half-billion years, clumps of gas collapsed enough to form the first stars and galaxies, whose energetic ultraviolet light ionized and destroyed most of the neutral hydrogen.
Although the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity, about 5 or 6 billion years after the Big Bang, a mysterious force now called dark energy began speeding up the expansion of the universe again, a phenomenon that continues today.
A little after 9 billion years after the Big Bang, our solar system was born.
The Big Bang
The Big Bang did not occur as an explosion in the usual way one think about such things, despite one might gather from its name. The universe did not expand into space, as space did not exist before the universe. Instead, it is better to think of the Big Bang as the simultaneous appearance of space everywhere in the universe. The universe has not expanded from any one spot since the Big Bang — rather, space itself has been stretching, and carrying matter with it.
Since the universe by its definition encompasses all of space and time as we know it, it is beyond the model of the Big Bang to say what the universe is expanding into or what gave rise to the Big Bang. Although there are models that speculate about these questions, none of them have made realistically testable predictions as of yet.
The universe is currently estimated at roughly 13.7 billion years old, give or take 130 million years. In comparison, the solar system is only about 4.6 billion years old.
This estimate came from measuring the composition of matter and energy density in the universe. This allowed researchers to compute how fast the universe expanded in the past.  With that knowledge, they could turn the clock back and extrapolate when the Big Bang happened. The time between then and now is the age of the universe.
Scientists think that in the earliest moments of the universe, there was no structure to it to speak of, with matter and energy distributed nearly uniformly throughout. The gravitational pull of small fluctuations in the density of matter back then gave rise to the vast web-like structure of stars and emptiness seen today. Dense regions pulled in more and more matter through gravity, and the more massive they became, the more matter they could pull in through gravity, forming stars, galaxies and larger structures known as clusters, superclusters, filaments and walls, with "great walls" of thousands of galaxies reaching more than a billion light years in length. Less dense regions did not grow, evolving into area of seemingly empty space called voids.
Until about 30 years ago, astronomers thought that the universe was composed almost entirely of ordinary atoms, or "baryonic matter." However, recently there has been ever more evidence that suggests most of the ingredients making up the universe come in forms that we can not see.
It turns out that atoms only make up 4.6 percent of the universe. Of the remainder, 23 percent is made up of dark matter, which is likely composed of one or more species of subatomic particles that interact very weakly with ordinary matter, and 72 percent is made of dark energy, which apparently is driving the accelerating expansion of the universe.
When it comes to the atoms we are familiar with, hydrogen makes up about 75 percent, while helium makes up about 25 percent, with heavier elements making up only a tiny fraction of the universe's atoms.
The shape of the universe and whether or not it is finite or infinite in extent depends on the struggle between the rate of its expansion and the pull of gravity. The strength of the pull in question depends in part on the density of the matter in the universe.
If the density of the universe exceeds a specific critical value, then the universe is "closed" and "positive curved" like the surface of a sphere. This means light beams that are initially parallel will converge slowly, eventually cross and return back to their starting point, if the universe lasts long enough. If so, the universe is not infinite but has no end, just as the area on the surface of a sphere is not infinite but has no beginning nor end to speak of. The universe will eventually stop expanding and start collapsing in on itself, the so-called "Big Crunch."
If the density of the universe is less than this critical density, then the geometry of space is "open" and "negatively curved" like the surface of a saddle. If so, the universe has no bounds, and will expand forever.
If the density of the universe exactly equals the critical density, then the geometry of the universe is "flat" with zero curvature like a sheet of paper. If so, the universe has no bounds and will expand forever, but the rate of expansion will gradually approach zero after an infinite amount of time. Recent measurements suggest that the universe is flat with only a 2 percent margin of error.
It is possible that the universe has a more complicated shape overall while seeming to possess a different curvature. For instance, the universe could have the shape of a torus, or doughnut.
Expanding Universe
In the 1920s, astronomer Edwin Hubble discovered the universe was not static. Rather, it was expanding, a find that revealed the universe was apparently born in a Big Bang.
After that, it was long thought the gravity of matter in the universe was certain to slow the expansion of the universe. Then, in 1998, the Hubble Space Telescope's observations of very distant supernovae revealed that a long time ago, the universe was expanding more slowly than it is today. In other words, the expansion of the universe was not slowing due to gravity, but instead inexplicably was accelerating. The name for the unknown force driving this accelerating expansion is dark energy, and it remains one of the greatest mysteries in science.

Comets: Formation, Discovery and Exploration

A comet is an icy body that releases gas or dust. They are often compared to dirty snowballs. Some researchers think comets might have originally brought some of the water and organic molecules to Earth that now make up life here.
The solid nucleus or core of a comet consists mostly of ice and dust coated with dark organic material, with the ice composed mainly of frozen water but perhaps other frozen substances as well, such as ammonia, carbon dioxide, carbon monoxide and methane. The nucleus might have a small rocky core.
As a comet gets closer to the sun, the ice on the surface of the nucleus begins turning into gas, forming a cloud known as the coma. Radiation from the sun pushes dust particles away from the coma, forming a dust tail, while charged particles from the sun convert some of the comet's gases into ions, forming an ion tail. Since comet tails are shaped by sunlight and the solar wind, they always point away from the sun.
The nuclei of most comets are thought to measure 10 miles (16 km) or less. Some comets have comas that can reach nearly 1 million miles (1.6 million kilometers) wide, and some have tails reaching 100 million miles (160 million kilometers) long.
We can see a number of comets with the naked eye when they pass close to the sun because their comas and tails reflect sunlight or even glow because of energy they absorb from the sun. However, most comets are too small or too faint to be seen without a telescope.
Comets leave a trail of debris behind them that can lead to meteor showers on Earth. For instance, the Perseid meteor shower occurs every year between August 9 and 13 when the Earth passes through the orbit of the Swift-Tuttle comet.
Orbital Characteristics
Asteroids classify comets based on the durations of their orbits around the sun. Short-period comets need roughly 200 years or less to complete one orbit, long-period comets take more than 200 years, and single-apparition comets are not bound to the sun, on orbits that take them out of the solar system. Recently, scientist have also discovered comets in the main asteroid belt — these main-belt comets might be a key source of water for the inner terrestrial planets.
Scientists think short-period comets, also known as periodic comets, originate from a disk-shaped band of icy objects known as the Kuiper belt beyond Neptune's orbit, with gravitational interactions with the outer planets dragging these bodies inward, where they become active comets. Long-period comets are thought to come from the nearly spherical Oort cloud even further out, which get slung inward by the gravitational pull of passing stars.
Some comets, called sun-grazers, smash right into the sun or get so close that they break up and evaporate.
In general, comets are named after their discoverer, either a person. For example, comet Shoemaker-Levy 9 got its name because it was the ninth short-periodic comet discovered by Eugene and Carolyn Shoemaker and David Levy. Spacecraft have proven very effective at spotting comets as well, so the names of many comets incorporate the names of missions such as SOHO or WISE.
Comet McNaught C/2009 R1 was visible on June 6, 2010.

Astronomers think comets are leftovers from the gas, dust, ice and rocks that initially formed the solar system about 4.6 billion years ago.
Comet Life Cycle
  • Departure
Some comets are not bound to the sun, on orbits that take them out of the solar system.
  • Extinction
Comets lose ice and dust each time they come near the sun, leaving behind trails of debris. Eventually, they can lose all their ices, with some turning into fragile, inactive objects similar to asteroids.
  • Breakup
Other comets, upon losing all their ices, break up and dissipate into clouds of dust.
  • Collisions
The orbits comets take sometimes end with them colliding with planets and their moons. Many impact craters seen in the solar system were caused by such collisions.
In antiquity, comets inspired both awe and alarm, "hairy stars" resembling fiery swords that appeared unpredictably in the sky. Often, comets seemed to be omens of doom — the most ancient known mythology, the Babylonian "Epic of Gilgamesh," described fire, brimstone, and flood with the arrival of a comet, and Emperor Nero of Rome saved himself from the "curse of the comet" by having all possible successors to his throne executed. This fear was not just limited to the distant past — in 1910, people in Chicago sealed their windows to protect themselves from what they thought was the comet’s poisonous tail.
For centuries, scientists thought comets traveled in the Earth's atmosphere, but in 1577, observations made by Danish astronomer Tycho Brahe revealed they actually traveled far beyond the moon. Isaac Newton later discovered that comets move in elliptical, oval-shaped orbits around the Sun, and correctly predicted that they could return again and again.
Chinese astronomers kept extensive records on comets for centuries, including observations of Halley's Comet going back to at least 240 BC, historic annals that have proven valuable resources for later astronomers.
A number of recent missions have ventured to comets. NASA's Deep Impact collided an impactor into Comet Tempel 1 in 2005 and recorded the dramatic explosion that revealed the interior composition and structure of the nucleus. In 2009, NASA announced samples the Stardust mission returned from Comet Wild 2 revealed a building block of life. The European Space Agency's Rosetta is scheduled to orbit Comet Churyumov-Gerasimenko in 2014 and deploy a probe to make the first landing on a comet.
Famous Comets
Halley's Comet is likely the most famous comet in the world, even depicted in the Bayeux Tapestry that chronicled the Battle of Hastings of 1066. It becomes visible to the naked eye every 76 years when it nears the sun. When Halley's Comet zoomed near Earth in 1986, five spacecraft flew past it and gathered unprecedented details, coming close enough to study its  nucleus, which is normally concealed by the comet's coma. The roughly potato-shaped, nine-mile-long (15 km) contains equal part ice and dust, with some 80 percent of the ice made of water and about 15 percent of it consisting of frozen carbon monoxide. Researchers believe other comets are chemically similar to Halley's Comet. The nucleus of Halley's Comet was unexpectedly extremely dark black — its surface, and perhaps those of most others, is apparently covered with a black crust of dust over most of the ice, and it only releases gas when holes in this crust expose ice to the sun.
The comet Shoemaker-Levy 9 collided spectacularly with Jupiter in 1994, with the giant planet's gravitational pull ripping the comet apart for at least 21 visible impacts. The largest collision created a fireball that rose about 1,800 miles (3,000 km) above the Jovian cloudtops as well as a giant dark spot more than 7,460 miles (12,000 km) across — about the size of the Earth —and was estimated to have exploded with the force of 6,000 gigatons of TNT.
A recent, highly visible comet was Hale-Bopp, which came within 122 million miles (197 million kilometers) of Earth in 1997. Its unusually large nucleus gave off a great deal of dust and gas — estimated at roughly 18 to 25 miles (30 to 40 kilometers) across — appeared bright to the naked eye.

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