This month sees a very special birthday: the 35th anniversary of the Hubble Space Telescope. The venerable old space telescope was launched on April 24, 1990, so now is the perfect time to celebrate this beloved instrument and the contributions it continues to make to science and our understanding of space.
Even though newer telescopes like the James Webb Space Telescope are more powerful than Hubble, it still fulfills an important role as an optical space telescope — meaning that it looks primarily in the same wavelengths that the human eye can see. Webb looks in the infrared portion of the spectrum, so by working together the two telescopes can get a fuller view of an object than either could get on their own.
Even now, Hubble continues to be fully utilized by astronomers and over its lifetime the telescope has produced thousands of images and endless data for scientists to study. Luckily for us, these images are also made public for everyone to enjoy.
We’re looking back on some of the best images that Hubble produced in the last year, starting with the image above: a new celebratory image released for the telescope’s 35th anniversary.
It shows the star cluster NGC 346, located in a satellite galaxy of the Milky Way called the Small Magellanic Cloud, which is a busy star forming region that is home to more than 2,500 baby stars.
Some of Hubble’s most striking images are of nebulae, which are clouds of dust and gas that are illuminated and glow in beautiful colors. This particular image captures a region on the outskirts of the Tarantula Nebula, located around 160,000 light-years away, which is host to some of the most massive stars we know of.
These huge stars are up to 200 times the mass of our sun, and they give off radiation which illuminates the dust around them.
As well as objects like nebulae, Hubble also observes entire galaxies like this one: a barred spiral galaxy called NGC 1672. Located 49 million light-years away, this galaxy has beautiful clear spiral arms reaching out from its center. The bubbles of red along the arms are hydrogen gas which glows due to radiation, all of which swirls around a particularly bright center called an active galactic nucleus.
This brightness comes from a supermassive black hole at the center which is hungrily feeding on dust and gas. As this material rotates around the black hole it forms a structure called an accretion disk, where it gets hotter and glows brightly.
This striking sight is the nebula RCW 7, located relatively nearby at just 5,300 light-years from Earth. These environments act as nurseries for new stars, as regions of the dust and gas collapse to form knots, attracting more material over time due to gravity and eventually forming the cores of new protostars.
This particular nebula is full of hydrogen ions, so is known as an H II region, as the ultraviolet radiation from the bright young stars ionizes the hydrogen and gives it a lovely soft pink color. While most Hubble images are taken in the visible light wavelength, this one also uses the near-infrared capabilities of Hubble’s Wide Field Camera 3 instrument.
Galaxies come in a number of shapes and sizes, so they are categorized by their features into groups based on structure. One such group is spiral galaxies, covering galaxies with arm-like structures that reach out from their centers — including our galaxy, the Milky Way.
Hubble captured this image of galaxy NGC 3430, which has such clear and elegant spiral arms that it was used to define the original classification of spiral galaxies. That work was done in the 1920s by Edwin Hubble, the American astronomer for whom the telescope is named.
This stunning image shows another part of the Tarantula Nebula, where clouds of colorful gas are criss-crossed by dark strands of dust. Located in the Large Magellanic Cloud, this nebula was observed as part of Hubble’s study of cosmic dust, which is important for the formation of stars and planets.
Cosmic dust is made up mostly of carbon or molecules combining silicon and oxygen called silicates, and when large amounts of this dust are present in the disks around stars, it is what eventually clumps together to forms the basis of new planets.
When massive stars come to the end of their lives and run out of fuel, they explode in enormous events called supernovas. These explosions are so bright that they can see seen from light-years away, and scientists track these events to study how they shape the regions around them.
This particular galaxy, called UGC 11861, has been host to three supernova explosions in the last thirty years, with events being spotted in 1995, 1997, and 2011. It is thought that this high rate of supernova acitvity is related to the active formation of new stars, which is visible in the glowing blue regions along the galaxy’s arms.
This charming object is called the Little Dumbbell Nebula, and is a famous target for amateur astronomers thanks to its nearby location (at 3,400 light-years from Earth) and its distinctive shape. The shape consists of a ring the middle (which we see side-on) and two large round structures called lobes on each side. It is believed that the ring in the center was formed by a pair of stars, called a binary, one of which threw off shells of dust and gas as it was dying.
The presence of its companion star caused this material to form into a disk shape along its orbit. The lobes then formed due to the extremely hot core of the remaining star, called a white dwarf, which has an incredible temperature of 120,000 degrees Celsius.
Hot gas is thrown outward and is “pinched in” by the ring, so it has puffed outward to form the lobe shapes.
