30 Years of Hubble: This year we are celebrating NASA Hubble Space telescope’s 30 years anniversary. Hubble has been revolutionizing modern astronomy for scientists, while taking the public on a wondrous journey of exploration and discovery.
In 2020, it will have been 30 years that NASA launched the Hubble Space telescope in orbit around the Earth on April 24th, 1990. The main goal of a getting a telescope in Space versus having it on Earth is to get rid of all the side effects of the atmosphere, which in turn degrade astronomical observations.
Unfortunately Hubble’s journey wasn’t a smooth ride from the get go. Indeed right after it was launched into orbit, NASA scientists discovered a flaw in the telescope’s mirror, which made the first images it took look blurry. Since the purpose of sending it to space was to get pin-point sharp images and avoid the drawbacks of Earth’s atmosphere, it was really disastrous news at the time.
It was far from ending the costing endeavor however, as Hubble was built to be serviced in Space by manned missions and also adjusted from Earth. In 1993, the Space shuttle Endeavour launched towards Hubble to repair it instead of its initial routine maintenance mission. Instead of replacing or mending the mirror, astronauts went on risky spacewalks to mount a redesigned camera with a redesigned corrective optics package for other instruments.
From then on, it could see all the wonders of the universe with a clarity that could never be achieved from Earth’s surface. The last servicing mission Atlantis launched in 2009 made sure that Hubble remains the world’s most powerful telescope ever built to this day.
One of the major things that Hubble has told us through its years of observation is that the universe is really active and dynamic. Everything is evolving, galaxies are spinning and moving, star systems are coming to life and also dying. We’ve learned that our own solar system is extremely dynamic as well. The best example is the different moons orbiting the planets, which are very interesting places in their own right. Some phenomena happening on planets are heavily affecting others on their moons and vice-versa. The best example is probably the plumes of water vapor exuding from Europa under Jupiter’s crushing gravity pull.
More recently the telescope has also had a significant impact on the search for exoplanets. Exoplanets are planets that are orbiting stars other than our Sun. Hubble has been able to detect water vapor in the atmosphere of these exoplanets, leading the way for potential future colonization.
On a bigger scale, Hubble has baffled scientists when observing the nature and distortion of the light emitted by deep-sky objects like galaxies. It helped them determine that the expansion rate of the universe is increasing. It gave birth to the theory of invisible dark energy that is pulling objects apart at an increasing speed.
One of the advantages of the Hubble Space telescope is that it is not only able to give us tremendous views of our universe in the visible light but also the invisible end of the electromagnetic spectrum. Our eyes can only detect the colors of the rainbow. Hubble can see in a wider spectrum way into the infrareds and ultraviolet. This ability has been a determining factor in the understanding of how stars are formed and die. Indeed our near universe is strewn with countless nebulae, these sometimes thick clouds of dust and gas. As colorful and spectacular as they can be, they also block the light from objects within or behind them.
By switching to an infrared vision, Hubble has helped reveal that nebulae are actually huge nurseries for baby stars as hot gases agglutinate at their center. When Hubble turned on its ultraviolet vision, it was able to detect auroras at Jupiter’s poles!
The Hubble Space telescope can see deep into space, which is to say looking far back in time. Indeed the light takes time to travel over the unfathomably huge distance of the universe. Some of the galaxies that Hubble has seen have taken billions of years for their light to reach us! One of the most famous pictures of Hubble are probably the ‘Deep Fields’. It is a series of images that took no less than 10 years to acquire.
Deep field observations are long-lasting observations of a particular region of the sky intended to reveal faint objects by collecting the light from them for an appropriately long time. The ‘deeper’ the observation is (i.e. longer exposure time), the fainter are the objects that become visible on the images. Astronomical objects can either look faint because their natural brightness is low, or because of their distance.
The Hubble Ultra Deep Field from 2004 represents the deepest portrait of the visible universe ever achieved by humankind. It reveals some of the first galaxies to emerge from the ‘Dark ages’ right after the Big Bang. By studying the stretching of the colors of these galaxies in visible light thanks to the Doppler effect, Hubble was able to determine the ‘reddest’ and thus the farthest galaxies. This image allowed astronomers to study star formation in a region 5 to 10 billion light-years away from us. The study is called the Ultraviolet Coverage of the Hubble Ultra Deep Field (UVUDF) project.
The Hubble Space telescope remains the most powerful telescope to this day. It continues to provide us with images and data that are vital to unravel the mysteries of the universe. In 2021, the James Webb Space telescope, Hubble’s successor is set to launch into orbit around the Earth. Scientists hope it will give significant complementary information that Hubble could not have achieved alone.