50 images of the universe from the Hubble Space Telescope
On April 24, 1990, the Space Shuttle Discovery launched, carrying the Hubble Space Telescope (HST, or just "Hubble"). This orbiting telescope was the first of NASA's Great Observatories. For 30 years, HST has provided astronomers with incredible scientific data on everything from solar system objects to some of the most distant galaxies in the cosmos. Hubble was named for American astronomer Edwin Hubble, who in the early 20th century helped establish that the universe is much bigger than the Milky Way and showed the cosmos is expanding.
To honor the 30th anniversary of the observatory's launch, Stacker collected 50 Hubble images, taken between 1990 and 2020, that express both the beauty of the universe and important scientific knowledge. HST is a bus-sized satellite containing a 2.4-meter-diameter mirror for focusing light from distant objects, along with a suite of instruments for photography, measuring light intensity, and taking the spectrum of various astronomical sources. Hubble is primarily an optical telescope, viewing the cosmos in the same type of light we can see, and it also has the ability to see into the infrared and ultraviolet parts of the spectrum of light. The size of the telescope and its location above Earth's atmosphere (with its pesky weather and distortions from air currents) make HST one of the best optical telescopes still in operation.
HST is jointly operated by NASA and the European Space Agency and was designed to be serviced by astronauts. Unfortunately, the Hubble needed to be repaired immediately after launch, when it turned out its mirror was slightly flawed. NASA astronauts installed additional mirrors to compensate for the flaws in 1993 and upgraded other scientific instruments on five different occasions, with the last upgrade being in 2009. Meanwhile, no plans are in the works to build an equivalent space telescope, so astronomers and nonscientists alike hope Hubble will continue to work indefinitely.
Click on for 50 images of the universe as seen from the Hubble Space Telescope.
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The Pillars of Creation (1995)
Perhaps Hubble's most popular image involves part of the Eagle Nebula known as the "Pillars of Creation." The Eagle Nebula is a star-forming region of the Milky Way, which means a cold cloud of gas and dust dense enough for gravity to take hold and collapse material into new stars. Ultraviolet light from these newborn stars erodes the nebula away, leaving the beautifully sculpted pillars in the image.
The Eagle Nebula in Infrared (2015)
The dense gas and dust of the Eagle Nebula are opaque in visible light but transparent to infrared. Hubble's infrared vision of the Pillars of Creation reveals they are harboring additional baby stars swaddled in gas.
Prelude to a Cosmic Explosion (1995)
In the early 1800s, the unremarkable star Eta Carinae in the southern constellation Carina grew suddenly brighter, briefly becoming the second-brightest star in the entire sky before fading. Later observations, including the one that produced this famous Hubble image, showed that Eta Carinae is actually two very massive stars shedding matter in two huge lobes of gas. Astronomers think these stars are unstable and will eventually explode in a supernova.
The Giant Next Door (2015)
Andromeda Galaxy (also known as M31) is the closest large galaxy to our Milky Way, near enough for astronomers to distinguish individual stars. This Hubble mosaic of a portion of Andromeda is the biggest image the telescope has made (constructed of 7,398 individual exposures!), containing over 100 million visible stars. Like the Milky Way, M31 is a spiral galaxy, with many of its brightest stars clustered in arms winding out from the galactic center.
The King of Planets (2017)
While much of Hubble's greatest work involves distant stars and galaxies, the observatory has also provided a wealth of information about our solar system. This 2017 image of Jupiter is part of an HST program to chart changes in the atmospheres of the giant outer planets. In particular, astronomers are watching the way Jupiter's famous Great Red Spot (known since the time of Galileo) is shrinking.
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Jupiter's Auroras (2016)
Auroras are caused when electrically charged particles cascade into a planet's atmosphere. On Earth, these are the northern and southern lights visible at high latitudes; Jupiter, being a much bigger planet with a huge magnetic field, has proportionally larger auroras. Hubble captured Jupiter's auroras using its ultraviolet instrument, and this picture was constructed by overlaying the UV image over a visible-light photo.
Galaxies in Collision (2010)
The Antennae Galaxies are a pair of galaxies in the process of colliding, a slow process taking hundreds of millions of years. This picture combines images from NASA's Great Observatories—Hubble (visible light), the Spitzer Infrared Observatory (infrared), and the Chandra X-ray Observatory (X-rays)—highlighting how these premiere space telescopes work together. The collision between the galaxies is producing new stars at a fast rate.
It's Full of Galaxies (1996)
In 1996, astronomers pointed HST at a small unremarkable spot on the sky nearly empty of stars and took pictures for 10 days to get a clear view deep into the cosmos. The 342 photos assembled from the project make up the Hubble Deep Field Survey and contain roughly 3,000 individual galaxies, some billions of light-years away. In fact, nearly everything you see in this image is a galaxy, revealing the diversity and evolution of galaxies over the history of the universe.
Echoes from an Explosion (2010)
In early 1987, astronomers spotted a new bright point of light in the nearby galaxy in the Large Magellanic Cloud: Supernova 1987A, the explosion of a massive star. Because it is the closest supernova in modern times, astronomers have been able to track the aftereffects of the explosion. This 2010 Hubble image shows expanding bubbles of matter blasted away from the dying star, producing beads of light where the material slammed into clumps of gas in the surrounding region.
The First Image of Another Star (1996)
Despite the power of modern telescopes like HST, most stars other than the sun are too far away to be anything but points of light. However, Hubble captured the first details on another star in 1996: the red giant Betelgeuse, which is part of the constellation Orion. As the diagram shows, Betelgeuse is so huge it's no longer spherical; in 2020, material ejected from the star blocked enough of its light that it dimmed visibly.
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