Tag Archives: Hubble Space Telescope

The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 on the space shuttle Discovery from Kennedy Space Center in Florida, and remains in operation. It is named after the astronomer Edwin Hubble (November 20, 1889 – September 28, 1953), the American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is generally regarded as one of the most important observational cosmologists of the 20th century. Hubble is known for showing that the recessional velocity of a galaxy increases with its distance from the earth, implying the universe is expanding, known as “Hubble’s law” although this relation had been discovered previously by Georges Lemaître, who published his work in a less visible journal.

Edwin Hubble is also known for providing substantial evidence that many objects then classified as “nebulae” were actually galaxies beyond the Milky Way. American astronomer Vesto Slipher had provided the first evidence for this argument almost a decade before. Hubble’s name is most widely recognized for the Hubble Space Telescope which was named in his honor, with a model prominently displayed in his hometown of Marshfield, Missouri.

Hubble Space Telescope
This photograph of NASA’s Hubble Space Telescope was taken on the fourth servicing mission to the observatory in 2009.

Some facts about HST

  • Hubble has made more than 1.2 million observations since its mission began in 1990.
  • Astronomers using Hubble data have published more than 14,000 scientific papers, making it one of the most productive scientific instruments ever built.
  • Hubble does not travel to stars, planets or galaxies. It takes pictures of them as it whirls around Earth at about 17,000 mph.
  • Hubble has traveled more than 3 billion miles along a circular low Earth orbit currently about 340 miles in altitude.
  • Hubble has no thrusters. To change pointing angles, it uses Newton’s third law by spinning its wheels in the opposite direction. It turns at about the speed of a minute hand on a clock, taking 15 minutes to turn 90 degrees.
  • Hubble has the pointing accuracy of .007 arc seconds, which is like being able to shine a laser beam on a dime 200 miles away.
  • Outside the haze of our atmosphere, Hubble can see astronomical objects with an angular size of 0.05 arc seconds, which is like seeing a pair of fireflies in Tokyo from your home in Maryland.
  • Hubble has peered back into the very distant past, to locations more than 13.4 billion light years from Earth.
  • The Hubble archive contains more than 120 terabytes, and Hubble science data processing generates about 10 Terabytes of new archive data per year.
  • Hubble weighed about 24,000 pounds at launch and currently weighs about 27,000 pounds following the final servicing mission in 2009 – on the order of two full-grown African elephants.
  • Hubble’s primary mirror is 2.4 meters (7 feet, 10.5 inches) across.
  • Hubble is 13.3 meters (43.5 feet) long — the length of a large school bus.

Sources

Are we the first?

In 1950, the Italian physicist Enrico Fermi was chatting with his colleagues at the Los Alamos National Laboratory(1). They talked about recent rise in UFO reports, then the conversation shifted to other subjects. But during the lunch, Fermi suddenly asked “Where is everybody?”. He was talking about the extraterrestrial life, especially intelligent life. He made some calculations on the probability of Earth like planets, the beginning of life, the probability of intelligent life and high technology and concluded that we ought to have been visited long ago and many times over.

But, there is no reliable evidence aliens have visited Earth and we have observed no intelligent extraterrestrial life with current technology nor has SETI found any transmissions from other civilizations. The Universe, apart from the Earth, seems “dead”.

So, where is everybody?
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Earth: a fast-moving Spacecraft

In fact, we’re all living in a fast-moving spacecraft named Earth. Our planet is moving around our sun in an elliptical (an ellipse which is very close to a circle) orbit. The Sun is (our solar system, the Sun, Earth and all the other planets and objects) whirls around the center of our galaxy. And, our galaxy and the other galaxies in our neighborhood are also rushing towards a structure called the Great Attractor, a region of space roughly 150 million light-years (one light year is about six trillion miles) away from us. This Great Attractor, having a mass 100 quadrillion times greater than our sun and span of 500 million light-years, is made of both the visible matter that we can see along with the so-called dark matter that we cannot see.
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