“Remember to look up at the stars and not down at your feet. Try to make sense of what you see and wonder about what makes the universe exist. Be curious”. This quote by Stephen Hawking clearly shows how we human beings, as a species always look at the stars to make sense of the universe and our existence. Our ancestors built telescopes to keep exploring stars and galaxies that were far away. These space telescopes have helped us gather immense knowledge about the vast universe and improve our lives back here on Earth.
The Hubble Space Telescope is certainly the most popular of all the space telescopes which have revolutionized astronomy since its launch and deployment in 1990. It has made more than 1.4 million observations throughout its lifetime. Hubble has tracked interstellar objects as they soared through our solar system, watched a comet collide with Jupiter, and discovered moons around Pluto, and much more. It is planned to be succeeded by the James Webb Space Telescope when it launches into space in 2021. It will be the largest and the most powerful and complex telescope to be ever built and launched into space.
What are space telescopes?
Space telescopes are observatories that observe distant stars, planets, galaxies, and other celestial objects in outer space. We place them into orbit and send them farther away to observe and record data of astronomical objects throughout the universe. They are free from the inconveniences ground telescopes face such as the filtering of ultraviolet frequencies, X-rays and gamma rays, the distortion of electromagnetic radiation, and even light pollution. Space telescopes are thus much more advantageous than ground telescopes and efficient for observation and data collection.
These telescopes can respond to electromagnetic waves ranging in length from about 115 nanometers in the far-ultraviolet region of the spectrum to about a million nanometers in the far-infrared. A projected lifetime for a space telescope is about 15 years on average. However, their lifetime can be lengthened if given proper servicing. The major space telescopes that are in outer space right now are the Hubble Space Telescope, the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, the Spitzer Space Telescope, Herschel Space Observatory, Planck Observatory, Kepler Mission and many more.
Types of space telescopes
Space observatories can be categorized into two main types. Astronomical survey telescopes map the entire sky, whereas other telescopes focus on selected astronomical objects. Some study special objects like the Sun. Others study the different types of light given off by objects in space. X-ray and gamma-ray telescopes study the hottest and most explosive objects in space. Similarly, infrared telescopes study the places where stars are born and can look into the centers of galaxies. Likewise, optical telescopes study the visible light from space, and ultraviolet telescopes study very hot stars.
How do they work
Earth’s atmosphere changes and blocks some of the light that comes from space. Space telescopes fly around the space or orbit high above Earth and its atmosphere. So, they can see space better than telescopes on Earth can. Such telescopes use digital cameras to takes pictures. They then use radio waves to send the pictures through the air back to Earth.
As the telescopes travel through space, their mirror captures light and directs it into its several science instruments. The mirrors in a telescope are the optics. The bigger the mirrors, the more light the telescope can gather. Light first hits the telescope’s main mirror, or primary mirror. It then bounces off the primary mirror and encounters a secondary mirror. The secondary mirror focuses the light through a hole in the center of the primary mirror that leads to the telescope’s science instruments such as cameras, spectrographs, spectrometers, and sensors. They help see the different kinds of light like ultraviolet, infrared, visible, and near-ultraviolet. The heat sensors help see objects hidden by interstellar dust, like stellar births and gaze into deepest space.
Why we need space telescopes
Space observatories or telescopes are undoubtedly the most important investigative tool in space exploration. They provide a means of collecting and analyzing radiation from celestial objects, even those in the far reaches of the universe. With the enhancements in our observational capabilities as of right now, we have been able to achieve more than ever before. At present, we use electronic computers, rockets, and spacecraft in conjunction with telescope systems for better observation. This has contributed hugely to advances in scientific knowledge about the solar system, the Milky Way Galaxy, and the universe as a whole.
We continuously discover new planets, solar systems, stars, and galaxies different from ours. Thus, this helps us study our universe more efficiently and uncover hidden facts. As of 2020, many space observatories have already completed their missions, while others continue operating on extended time. Newer telescopes like the James Webb Space Telescope is planned to launch in 2021. However, the future availability of other space telescopes and observatories depends on timely and sufficient funding. Nevertheless, we must keep doing everything we can to progress further and find the answers to the universe.
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I am a content writer and editor at Modern Writes. I am an undergraduate student studying electrical and electronics engineering in Kathmandu University, Nepal. My main interests include space technology, telecommunications, and electronics. I enjoy reading, music, and fitness activities.