For 10 days in 1995, the Hubble Space Telescope turned its gaze to a small and seemingly empty space. The result was “Hubble’s deep field”, a very-not-empty image packed with the 3,000 weakest galaxies ever discovered.
Hubble has been at the center of such remarkable discoveries for more than 30 years, detecting the atmospheric composition of exoplanets, using light wavelengths to help us understand how stars form, and giving humanity its first seat in a supernova.
Based on Hubble’s science, NASA is now preparing to launch its successor: the James Webb Space Telescope (JWST). The telescope (whose name has sparked controversy) will be able to look even further into the past by going beyond visible light and primarily observing in the infrared part of the spectrum. As the universe expands, light emitted by the first luminous objects has been stretched out or “redshifted” to longer wavelengths. JWST is designed to capture these wavelengths with sensitivity and resolution so powerful that it will be able to observe light arriving from just a few hundred million years after the Big Bang.
Yet our best view of the universe in decades came from Hubble. Here is a look back at some of the spectacular images that helped us better understand our universe.
This giant red nebula and its smaller blue neighbor are part of a large star-forming region in the large Magellanic cloud, a satellite galaxy in the Milky Way, about 163,000 light-years away. The image is nicknamed “Cosmic Reef,” says NASA because the red nebula resembles a coral reef floating in a sea of stars. The sparkling central region is a group of fierce stars, each 10 to 20 times more massive than our sun.
A rare image of a pair of overlapping galaxies, called NGC 3314. The two galaxies look as if they are colliding, but they are actually separated by tens of thousands of light-years, or about ten times the distance between our Milky Way and the nearby Andromeda galaxy, says NASA. Despite their appearance here, the motion of the two galaxies indicates that they are both relatively undisturbed and moving in markedly different directions – not on any collision course.
Star cluster R136
In the central region of the Tarantula Nebula, about 170,000 light-years from Earth, lies a dense cluster of young stars (seen at bottom right). Among the hundreds of young blue stars, the most massive stars to date have been found in the universe, NASA says. In the most dense, central region of this cluster, astronomers have found nine stars with masses greater than 100 times the mass of our sun.
A small part of the nebula, the remnants of a supernova remnant, was formed about 8,000 years ago by the death of a star that was 20 times the mass of our sun. As massive stars tend to do, “it lived fast and died young,” and ended its life in a catastrophic release of energy. The shock waves and debris from the supernova sculpted the delicate tips of the haze train of ionized gas. In this image, red corresponds to hydrogen, green to sulfur and blue to oxygen.
Light echo from a red supergiant star
This image of the red supergiant star V838 Monocerotis reveals dramatic changes in the illumination of its surrounding dust clouds. The effect, called a light echo, never revealed previously seen dust patterns when the star suddenly brightened up in January 2002. It temporarily became one of the brightest stars in the Milky Way – 600,000 times brighter than our sun – before fading in April 2002. Unlike a normal nova explosion, the V838 Monocerotis did not emit its outer layers, NASA reported. Instead, it ballooned in size, and its surface temperature dropped to temperatures not much hotter than a bulb. Scientists are not sure why it erupted in this way, but say the eruption may represent a rarely seen transitional phase in a star’s evolution.
Herbig-Haro Object 24
Newly formed stars sometimes emit thin, warm rays of ionized gas, creating a lightsaber-like effect known as an Herbig-Haro object. The young star hidden by dust in the center of this image is located in our own Milky Way, about 1,350 light-years away. Hubble observed this HH object in infrared; according to NASA, these young star planes will be ideal targets for JWST, which will have even larger infrared wavelengths to see deeper into the dust around newly formed stars.
The Butterfly Nebula
As smaller stars die, they push their outer layer of gas into space over about 10,000 years, leaving a hot core known as a white dwarf. Radiation from the white dwarf in the center of this image illuminates the outgoing gas, creating a striking formation called a planetary nebula. According to NASA, the name comes from the early days of astronomy, when observers believed that the dark shapes they observed could be related to planets. With an estimated surface temperature of more than 400,000 degrees Fahrenheit, the central star of this planetary nebula is one of the hottest stars ever.
Jupiter and Europe
This fairly new image of Jupiter captured not only the gas giant’s famous large red spot, but a bright white, expansive storm on the mid-northern latitudes traveling around the planet at 350 miles per hour. And under the big red spot, Oval BA continues – called Red Spot Jr. With swinging and now changes from its typical whitish color to redder tones. The icy moon Europa, which is believed to contain potential ingredients for life, is visible to the left of Jupiter.
In the productive star nursery known as the Carina Nebula, chaos unfolds on top of a three light-year-old pillar of gas and dust. Burning radiation and streams of charged particles from super-hot newborn stars in mist form and compress the column, causing new stars to form in it. At the same time, the column is being torn from within, NASA reports, as infant stars buried inside it fire gas jets that can be seen flowing from its peaks.
Hubble has for years documented the fusion of two spiral galaxies called the “Antenna Galaxies”. The pair began interacting a few hundred million years ago, NASA reports, and during the collision, billions of stars will be formed. This collision is so violent that stars have been torn from their host galaxies to form a streaming arc between the two, the inspiration for their name. And the rate of star formation is so high that the Antenna galaxies are said to be in a state of stellar eruption, a period in which all the gas in the galaxies is used to form stars. This stage cannot last forever, nor can the separate galaxies; eventually they will merge into a large elliptical galaxy.