Hubble Space Telescope, a wonder of optical telescopes, was launched into low Earth orbit in the 1900s and remains operational till now. It has been the most versatile and one of the most useful telescopes ever built, well known both as a research tool and public relations boon for astronomy. This telescope was named after Edwin Hubble.

The Hubble Space Telescope in orbit

Hubble features a 2.4-meter mirror, and its instruments allow it to observe the Cosmos in Infrared, Ultraviolet and near infrared regions of electromagnetic spectrum. Built in the 1996, it has provided intriguing images of the background of space, transcending dimensions into space and laying down tools to determine the most breathtaking of results ever discovered in physics, such as determining the rate of expansion of Universe.

Hubble is in constant need of repairs by the astronauts in orbit. A total no of 5 such Space Shuttle missions have been launched till now which has repaired, replaced and regulated the instruments on board the telescope with the last mission launched in 2009.

   Astronaut Owen Garriott working next to Skylab’s crewed solar space observatory, 1973

Important scientific discoveries

  1. Expansion of the Universe = With its increased high definition resolution images, Hubble helped scientists discover that rather than decelerating under the effect of gravity, the universe was actually expanding at an accelerating rate based on the study of IA supernovae. The cause of the expansion remains unknown as is attributed to dark energy.

How does the Universe expand? – Science Experiments for Kids

  1. Age of the Universe = The primary missions of Hubble included calculating the distance to Cepheid variables which was further used to calculate the value of Hubble constant. This in turn was related to the age of the Universe and gave it to be 13 billion years with 10% uncertainty. Before the launch of Hubble, scientists used to predict this value to be 10 to 20 billion years.

  1. Providing greater resolution images = Along with determining age of the universe, Hubble also opened a window of opportunity for the scientists into a different realm of cosmos for the scientists. With Hubble Deep Field, Hubble ultra-deep field and Hubble extreme-deep field, Hubble provided high quality images of patches of sky with unmatched sensitivity. These images are the deepest ever obtained at optical wavelengths and obtain a mesmerizing view of the whole cosmos.

  1. Mass and size of Milky Way = Observation from Hubble space telescope and European Space agency’s Gaia telescope were analysed to determine the mass of Milky Way galaxy which came out to be 1.5 trillion solar units with a radius of 129,000 light years.

                                                                    Milky Way Galaxy           

The telescope is expected to be operation until 2030-2040 before becoming permanently un-operational. It has indeed been an exciting journey with Hubble unravelling mysteries of the cosmos with its each image and taking the breath of anyone who sees such image.

Its successor James Webb Space Telescope is expected to be launched in 2021.

Written by Sukhjit Singh

Edited by Shweta Mittal