The Hubble Space Telescope turned 18 this year. During its 18 years in orbit, it has returned spectacular images and expanded our knowledge of everything from the age of the universe to how planets form. Outstanding work for a telescope that nearly failed to launch, and turned out to be visually impaired when it did.
The Challenger disaster delayed Hubble's scheduled launch in 1986. Discovery finally took the telescope into orbit in 1990. Then the first images came back, and showed a nearly fatal flaw with the primary mirror. What a difference 2.3 micrometers makes! The flaw meant that Hubble had no problem with bright objects, but couldn't see faint ones in enough detail to perform its mission. So, of course, scientists designed spectacles, and Hubble took a clear, deep look into space. It's appropriate that it was launched on a shuttle named Discovery, because its discoveries have been truly incredible.
13.7 Billion Years
The best available information indicates that the age of the universe is 13.7 billion years. Hubble has helped to measure the age of the universe using two different methods. The first method involves measuring the speeds and distances of galaxies. Because all of the galaxies in the universe are generally moving apart, we infer that they must all have been much closer together sometime in the past. Knowing the current speeds and distances to galaxies, coupled with the rate at which the universe is accelerating, allows us to calculate how long it took for them to reach their current locations. The answer is about 14 billion years. The second method involves measuring the ages of the oldest star clusters [link]. Globular star clusters orbiting our Milky Way are the oldest objects we have found and a detailed analysis of the stars they contain tells us that they formed about 13 billion years ago. The good agreement between these two very different methods is an encouraging sign that we are honing in on the universe’s true age.
400 Million Years After the Big Bang
Called the Hubble Ultra Deep Field, the view represents the deepest portrait of the visible universe ever achieved by humankind. The snapshot reveals the first galaxies to emerge from the so-called "dark ages," the time shortly after the big bang when the first stars reheated the cold, dark universe. The new image should offer new insights into what types of objects reheated the universe long ago.
Fate of the Sun
A new image from NASA's Hubble Space Telescope shows the colorful "last hurrah" of a star like our sun. The picture was taken on Feb. 6, 2007, by Hubble's Wide Field and Planetary Camera 2, which was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. The star is ending its life by casting off its outer layers of gas, which formed a cocoon around the star's remaining core. Ultraviolet light from the dying star makes the material glow. The burned-out star, called a white dwarf, is the white dot in the center. Our sun will eventually burn out and shroud itself with stellar debris, but not for another 5 billion years.
Astronomers have long puzzled over why a small, nearby, isolated galaxy is pumping out new stars faster than any galaxy in our local neighborhood. Now NASA's Hubble Space Telescope has helped astronomers solve the mystery of the loner starburst galaxy, called NGC 1569, by showing that it is one and a half times farther away than astronomers thought. The extra distance places the galaxy in the middle of a group of about 10 galaxies centered on the spiral galaxy IC 342. Gravitational interactions among the group's galaxies may be compressing gas in NGC 1569 and igniting the star-birthing frenzy. "Now the starburst activity seen in NGC 1569 makes sense, because the galaxy is probably interacting with other galaxies in the group," said the study's leader, Alessandra Aloisi of the Space Telescope Science Institute in Baltimore, Md., and the European Space Agency. "Those interactions are probably fueling the star birth." The farther distance not only means that the galaxy is intrinsically brighter, but also that it is producing stars two times faster than first thought. The galaxy is forming stars at a rate more than 100 times higher than in the Milky Way. This high star-formation rate has been almost continuous for the past 100 million years. Discovered by William Herschel in 1788, NGC 1569 is home to three of the most massive star clusters ever discovered in the local universe. Each cluster contains more than a million stars.
100,000th Orbit: Star Birth
Hubble peered into a small portion of the Tarantula nebula near the star cluster NGC 2074. The region is a firestorm of raw stellar creation, perhaps triggered by a nearby supernova explosion. It lies about 170,000 light-years away and is one of the most active star-forming regions in our local group of galaxies. The image reveals dramatic ridges and valleys of dust, serpent-head "pillars of creation," and gaseous filaments glowing fiercely under torrential ultraviolet radiation. The region is on the edge of a dark molecular cloud that is an incubator for the birth of new stars. The high-energy radiation blazing out from clusters of hot young stars is sculpting the wall of the nebula by slowly eroding it away. Another young cluster may be hidden beneath a circle of brilliant blue gas.
Explore Strange New Worlds
NASA's Hubble Space Telescope has discovered carbon dioxide in the atmosphere of a planet orbiting another star. This breakthrough is an important step toward finding chemical biotracers of extraterrestrial life. The Jupiter-sized planet, called HD 189733b, is too hot for life. But the Hubble observations are a proof-of-concept demonstration that the basic chemistry for life can be measured on planets orbiting other stars. Organic compounds also can be a by-product of life processes and their detection on an Earthlike planet someday may provide the first evidence of life beyond our planet. Previous observations of HD 189733b by Hubble and the Spitzer Space Telescope found water vapor. Earlier this year, Hubble found methane in the planet's atmosphere. "Hubble was conceived primarily for observations of the distant universe, yet it is opening a new era of astrophysics and comparative planetary science," said Eric Smith, Hubble Space Telescope program scientist at NASA Headquarters in Washington. "These atmospheric studies will begin to determine the compositions and chemical processes operating on distant worlds orbiting other stars. The future for this newly opened frontier of science is extremely promising as we expect to discover many more molecules in exoplanet atmospheres."
There is too much. I have merely summed up, not 'splained. Go. Look. Marvel.