The Hubble Space Telescope was launched into low-earth orbit on April 24th 1990. It has been observing the universe for 33 years. But how far can the Hubble Telescope see?
We’ll examine what it’s seen and discovered, how big it is and who it was named after. We’ll also look at what is due to take the place with the Hubble Space Telescope.
What Can The Hubble Telescope See?
Hubble was designed to collect about 40,000 times more light than the human eye. It is capable of examining ultraviolet, visible and infrared light waves. The solar-powered telescope can see for billions of light years.
A light year is the distance that light travels in one year in a vacuum. At a speed of 186,000 miles per second (300,000 km per second), light travels 5,865,696,000,000 miles (9,439,922,663,424 km) in a year.
To understand how far 1 billion light years is, you need to add 9 zeros to the end of that figure. For ten billion light years, add another zero.
So far, Hubble has observed a galaxy designated GN-z11 at a distance of 13.4 billion light-years. Incidentally, the James Webb Space Telescope has already surpassed that distance.
Since its launch, Hubble has made over 1.5 million observations. It has produced some of the most remarkable images of the cosmos.
Its Deep Field and Ultra Deep Field images (shown below) showed thousands of galaxies in various stages of their evolution.
How Big Is The Hubble Telescope?
The Hubble Space Telescope is 43.5 feet (13.3m) long and 14 feet (4.3m) wide at the rear, where the scientific instruments are housed. It weighs around 27,000 pounds (12,245kg) and is about the same size and weight as a school bus.
Power for the telescope comes from two solar arrays. These convert sunlight into energy, which is stored in six large batteries that act as a backup when the telescope is in the earth’s shadow and blocked from the sun.
In the center of Hubble, four reaction wheels are used to reorient the telescope. Each of these wheels weighs 100 pounds (45.4kg).
They operate according to Newton’s Third Law of Motion; for every action, there is an equal and opposite reaction. Changing the rotation of one or more wheels produces a torque that will force the telescope to rotate.
The wheels are controlled by Hubble’s main computer, which knows where the telescope needs to turn based on its target schedule.
Hubble also has six high-precision gyroscopes which detect its direction and rate of motion. However, in regular operation, it typically only uses three of them.
What Has It Discovered?
Since collecting images, the Hubble Space Telescope has helped scientists better understand galaxies, including how they form and evolve.
Thanks to Hubble’s deep-field imagery, some of the farthest galaxies have been observed. As detailed earlier, JWST has now surpassed this, which it was designed to do just that.
Its most famous discovery is the Hubble Ultra Deep Field (shown above), the deepest image of our universe made at visible and near-infrared wavelengths. The image revealed over 10,000 galaxies in a tiny piece of the sky.
Thanks to Hubble, scientists now know that most galaxies are host to supermassive black holes. It also helped in the understanding of dark matter by mapping its presence.
Dark matter makes up most of the universe’s structure and mass.
The telescope has observed things scientists would never have imagined, such as backward-spinning, ring-shaped, and giant elliptical galaxies.
It has helped us better to understand our own galaxy, the Milky Way. Even today it continues to take stunning images of the deepest reaches of space to educate further and enthral us.
Hubble is expected to be retired sometime in the 2030’s. It was originally expected to be in operation for just 15 years.
Who Is The Hubble Telescope Named After?
Dr. Edwin Hubble studied at the Mt Wilson Observatory near Pasadena, California during the 1920s. It’s doubtful that he ever imagined a telescope would be named after him or that it would be a space telescope.
Hubble’s work focused on interstellar clouds of glowing gasses and dust. He discovered the first variable star in the Andromeda galaxy and found that it could be used to calculate its distance from the Earth.
The astronomer also discovered that the universe was expanding and the rate at which it was occurring. What he determined was that objects farther away were moving away more quickly. The relationship between the speed and the distance became know as the ‘Hubble Constant’.
His insight into the expanding universe was the foundation of the Big Bang theory.
To recognize the contribution that Dr. Hubble made to the field of astronomy NASA decided to name the world’s first space-based telescope after him.
It seems a fitting tribute to a man who contributed so much to our understanding of the universe and its origins.
What Will Replace The Hubble Telescope?
Sadly, the Hubble telescope will not last forever. In fact, it is slowly falling back to earth, albeit very slowly. This is because it doesn’t have its own propulsion system.
The estimated date for its re-entry is thought to be no earlier than 2027 and more like 2038.
The common misconception is that the James Webb Space Telescope would ‘replace’ Hubble, but the two are quite different.
In a sense, the JWST will be Hubble’s successor, although they will operate simultaneously for several more years.
The James Webb Space Telescope was launched on Christmas Day 2021 and is the largest, most powerful space telescope ever built.
It has the ability to see images of some of the very first galaxies ever formed as well as into dust clouds where new stars and planets are born.
It is as tall as a three-storey building and the same length as a tennis court. After launch, it had to be folded like origami and then slowly unfolded itself perfectly, post-launch.
Its most striking feature is its sun-shield which protects the instruments and mirrors.
JWST solely uses infrared wavelengths to make observations and has already produced some of the most remarkably sharp and clear images of distant galaxies and nebulae.
More recently, a new space telescope has been launched. The Euclid Space Telescope will perform a survey mission to image a significant portion of the sky and measure the distance to the objects imaged.
As we develop new tools, we will see farther into the universe. However, we will never see past the Cosmological Horizon.
Final Thoughts
We hope you’ve enjoyed this guide to how far the Hubble telescope can see and that you have found it informative.
Update: On May 23, 2024, NASA decommissioned one of the spacecraft’s gyroscopes after a few months of intermittent failures. Hubble uses gyroscopes to aim the telescope at targets. As a result, the telescope’s aiming is affected, which limits its performance.
Hi, my name is Jason Anderson, and I am a Physics Professor. Ever since I was a kid, I’ve been fascinated with space, the universe, the moon, you name it. I spent hours and hours at the planetarium close to my hometown, wondering what else could be out in the universe.
Since then, I’ve been an avid stargazer and astronomer, and love nothing more than spending my time charting stars, observing planets, and finding constellations.
This is why I decided to start Telescope Guru. I only wish to share this fun pastime with the world. With this site, I hope to answer all of your questions relating to astronomy, telescopes, and stargazing.
