Sanuj Raj
5 min readApr 5, 2021


Hubble was one of the most revolutionary objects not only in space science but in all of the 20th century. It defined an era where we came a step closer to answer the questions, that humans have been asking since the inception, “Are we alone in this universes or is there someone out there just like us?”. It was put in space through the collective effort of hundreds of scientists. It was launched into orbit on April 24, 1990, on the Discovery space shuttle.
Hubble was the brainchild of Edwin Powell Hubble. He made some extraordinary discoveries and broke many predictions.

He gave the Hubble law in 1929 which states that,
“The galaxies are moving away from the earth at speeds proportional to their distance and by a phenomenon known as redshift. The farther the galaxy the redder it appears, and through this, we were able to know the age of the universe.”

The Hubble is based on interesting telescope phenomena which are called reflecting telescope.
In this technique, a concave mirror is used in the telescope to make the reflection of the upcoming image as short as possible so that it falls perfectly on the eyepiece. This directly allows for a much bigger telescope than ever before.
Reflecting Telescope has some more advantages such as:
1. There is no spherical abbreviation in the mirror.
2. Mechanical support is much less of a problem since the weight of these kinds of mirrors is significantly less.

Hubble Deep Field

The Hubble deep field is one of the most important experiments that happened in astronomy. Basically, the Hubble was looking at a random piece of sky equivalent to a looking from a straw with an area of about 2.6 arcminutes. The Hubble was focused on the constellation Ursa major for 10 days. This experiment was carried out the year 1995.

The Actual Hubble Deep Field Image

A sophisticated image was generated from the experiment which had around 3000 small objects and all of those objects were identified to be galaxies. This observation was astounding for scientists because they were not expecting to see anything out of the experiment but they ended up with many great discoveries.

It is said that there are more number of galaxies in the universe than the grains of sand present on all the beaches of the world combined.


Hubble was NASA’s one of biggest achievement as well as one of the biggest blunders they ever made of the 20th century. Hubble was a masterpiece 50 years in the making, it had the vision of many scientists to put a telescope in space to see out in the universe better.

NASA has a long history of screwing up things, from faking the moon landings to killing 14 astronauts in the space shuttle program. Hubble was no exception either as the primary mirror was polished too much. The company that was given the task was one of the most sought-after companies of that time which specialized in making huge mirrors.
Due to this abrasion, the images that were captured were blurred and the focus point of the oncoming infinite rays of the distant galaxies was distorted and was not focused on a single point.

The Primary Mirror of Hubble

The parallel rays coming from infinity are reflected onto a convex mirror which helps in converging the focal point on the observing camera in a short framework. The convex mirror just helps to better utilize the merely available space for convergence of the rays, it does not add any value in the pictures. Hubble was using the best camera available at the time.

The Working of a Telescope

To mend this the only solution that came out, was to change the primary over polished mirror in space by literary going there. This news made the world go mad as lots of money was put into the program and more additional money was needed to correct somebody’s mistake.
It was in the best interest of everyone to spend that extra money and make the Hubble do what it is capable of. So after preparing for over a year, astronauts went to service the Hubble and with a flawless repair completed the task. The only problem they encountered was not properly closing the latch of the door, but they did it eventually.
After this repair work, the Hubble was serviced two more times for changes of certain components.

The next frontier replacing the Hubble is the “infamous” James Webb telescope which has been delayed for over a decade and cost $10 billion in overbudget. Unlike the Hubble, everything on the James Webb had to be perfect as it is sent in an orbit which is 1 million miles from Earth and humans have not even crossed the LEO (Low Earth Orbit) which is just 300 miles above our heads. So servicing the telescope is out of the question. Due to these factors, NASA is delaying the launch.

The Next Frontier “James Webb”

For more information on the James Webb Telescope visit:


The photo on the left is the best Hubble could capture images of Pluto, and on the right is Pluto

The Hubble was made for capturing distant objects and not things in the solar system, because of this until the New Horizons mission in 2016 we didn’t know how Pluto looked. We only had theoretical knowledge of the dwarf planet and not an actual image, until 2016 we only theoretically knew that Pluto was round. We had visited all the planets except for Pluto until the New Horizons mission.
The mission was an astonishing feat in itself as it took 9 years to complete.


  • It helped found out the age of the universe, through observing the most distant galaxies through a phenomenon called redshift.
    The age of the universe is around 13.8 billion years.
  • It helped uncover the rate at which the universe is expanding.
  • The Hubble created a 3D map of dark matter.
  • It also helped to discover the 2 moons of Pluto, Nix, and Hydra.
  • From the day the Hubble was born it has made 1.3 million unique observations including some of the most astonishing photos of the vast universe.
The Pillars of Creation