On April 24, 1990...

...the Space Shuttle Discovery blasted off from Cape Canaveral, Florida, carrying the 1.5 billion dollar Hubble Space Telescope.


Every 97 minutes, the Hubble Space Telescope completes a spin around Earth, moving at the speed of about five miles per second (8 km per second) — fast enough to travel across the United States in about 10 minutes. As it travels, the telescope's mirror captures light and directs it into its several science instruments.

People often mistakenly believe that a telescope's power lies in its ability to magnify objects. Telescopes actually work by collecting more light than the human eye can capture on its own. The larger a telescope's mirror, the more light it can collect, and the better its vision.


The Hubble's primary mirror is 94.5 inches (2.4 m) in diameter. This mirror is small compared with those of current ground-based telescopes, which can be 400 inches (1,000 cm) and up, but Hubble's location beyond the atmosphere gives it remarkable clarity.

Hubble's discoveries have transformed the way scientists look at the universe. Its ability to show the universe in unprecedented detail has turned astronomical conjectures into (more) concrete certainties. It has winnowed down the collection of theories about the universe even as it sparked new ones, clarifying the path for future astronomers.


Among its many discoveries, the Hubble space telescope has revealed the age of the universe to be about 13 to 14 billion years, much more accurate than the old range of anywhere from 10 to 20 billion years. The telescope played a key role in the discovery of dark energy, a mysterious force that is causing the expansion of the universe to accelerate.

It is named, most fittingly, after the American astronomer Edwin Hubble.

Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer who profoundly changed our understanding of the universe by demonstrating the existence of galaxies other than our own, the Milky Way.

He also discovered that the degree of "Doppler shift" (specifically "redshift") observed in the light spectra from other galaxies increased in proportion to a particular galaxy's distance from Earth and helped establish that the known universe is expanding which in turn led to refinements in the "Big Bang" theory.

In 1919, Hubble was offered a staff position in California by George Ellery Hale, the founder and director of the Carnegie Institution's Mount Wilson Observatory, near Pasadena, California, where he remained on the staff until his death. Shortly before his death, Mount Palomar's giant 200-inch (5.1 m) reflector Hale Telescope was completed, and Hubble was the first astronomer to use it.

Happy Birthday Hubble! And thanks for all the glorious pictures of the cosmos.