Hubble Space Telescope
From the very beginning of astronomy, from the time of Galileo, astronomers have one common goal: to see more, to see further, to see deeper. And the Hubble Space Telescope, launched in 1990, is a huge step in that direction. The telescope is located in Earth’s orbit above the atmosphere, which could distort and not transmit radiation coming from space objects. Due to its absence, astronomers obtain the highest quality images with Hubble. It is almost impossible to overestimate the role that the telescope played for the development of astronomy – Hubble is one of the most successful and long-term projects of the NASA space agency. He sent hundreds of thousands of images to the Earth, shedding light on many secrets of astronomy. He helped determine the age of the Universe, identify quasars, prove that massive black holes are located in the center of galaxies, and even set up experiments to detect dark matter.
Hubble Hubble’s discoveries have changed the way astronomers look at the universe. The ability to see in great detail helped turn some astronomical hypotheses into facts. Many theories were discarded in order to go in one right direction. Among Hubble’s achievements, one of the main ones is the determination of the age of the Universe, which today scientists estimate at 13-14 billion years. This is undoubtedly more accurate than previous data of 10–20 billion years. Hubble also played a key role in detecting dark energy, the mysterious power that makes the universe expand at an ever-increasing rate. Thanks to Hubble, astronomers were able to see galaxies at all stages of their development, starting from the formation that took place in the young Universe, which helped scientists understand how their origin took place. Using a telescope, protoplanetary disks, gas and dust accumulations around young stars were found around which new planetary systems would soon appear (by astronomical standards, of course). He was able to find sources of gamma-ray explosions – strange, incredibly powerful energy emissions – in distant galaxies during the collapse of supermassive stars. And this is only part of the discoveries of a unique astronomical instrument, but already proving that the $ 2.5 billion spent on creating, putting into orbit and servicing is the most profitable investment on the scale of all mankind.
Hubble has amazing performance. The entire astronomical community takes advantage of its ability to see the depths of the universe. Each astronomer can send a request for a specific time of using his services, and a team of specialists decides whether this is possible. As a rule, a year passes after observation, before the astronomical community receives the research results. Since the data obtained using the telescope is accessible to everyone, any astronomer can conduct his research, coordinating the data with observatories around the world. Such a policy makes research open, and therefore more effective. However, the unique capabilities of the telescope also mean the highest level of demand for it – astronomers around the world are fighting for the right to use the Hubble services in their free time from the main missions. Each year, more than a thousand applications are received, among which the best according to experts are selected, but according to statistics only 200 are satisfied – only a fifth of the total number of applicants conduct their research using Hubble.
Why was it necessary to bring the telescope into near-Earth space, and thanks to which the apparatus is so in high demand among astronomers? The fact is that the Hubble telescope was able to solve two problems of ground-based telescopes at once. Firstly, the blurring of the signal from the Earth’s atmosphere limits the capabilities of ground-based telescopes, regardless of their technical perfection. Thanks to atmospheric blur, we see stars blinking when we look at the sky. Secondly, the atmosphere absorbs radiation with a certain wavelength, most of all ultraviolet, x-ray and gamma radiation. And this is a serious problem, since the study of space objects is more effective, the larger the energy range is taken.
And precisely in order to avoid the negative influence of the atmosphere on the quality of the obtained images, the telescope is located above it, at a distance of 569 kilometers above the surface. At the same time, the telescope makes one revolution around the Earth in 97 minutes, moving at a speed of 8 kilometers per second.
The Hubble telescope is a reflector of the Ritchie-Chretien system, or an improved version of the Cassegrain system, in which light initially enters the main mirror, is reflected and falls on the secondary mirror, focusing the light and directing it into the system of scientific instruments of the telescope through a small hole in the main mirror. Often people mistakenly believe that a telescope is magnifying an image. In fact, it only collects the maximum amount of light from the object. Accordingly, the larger the main mirror, the more light it will collect and the sharper the image will be. The second mirror only focuses the radiation.