Hubble Vs James Webb: Comparing World’s 2 Powerful Space Telescopes

James Webb is the most advanced space telescope ever made, but it is frequently referred to as Hubble’s replacement, but in real term we should call it Hubble’s successor. After all, its scientific objective is inspired by Hubble’s findings.

More distant objects in general are redshifted more strongly, and their light wavelengths are pushed from the UV and optical region to the near-infrared part of spectrum.

In order to observe these distant objects (such as the earliest galaxies produced in the Universe), an infrared telescope is required.

For this reason, scientists have come up with what we call now the world’s most powerful telescope, i.e. James Webb Space Telescope.

Though JWST is often referred to as Hubble’s successor, there are a lot of differences between them. Let us cover some of the major differences described below:

Difference In Costs Of Hubble Vs James Webb

In 1990, by the time Hubble was rocketed into orbit, it was years late and millions over budgeted. Webb is also years late with huge cost overruns. NASA’s estimated number for Hubble from its 1970s development until now is $16 billion, adjusted for inflation.

That doesn’t include all the shuttle flights for launch and repairs. Webb’s price tag is an estimated $10 billion; that includes the first five years of operation. So, from the cost perspective, we can say that Webb is more cost effective than Hubble.

Difference In Study Hubble Vs James Webb Telescope

Another reason James Webb isn’t a replacement for Hubble is that its capabilities aren’t comparable. Webb will focus on infrared wavelengths, whereas Hubble will examine optical and ultraviolet wavelengths (though it has some infrared capability). Webb also has a far larger mirror than Hubble.

Hubble orbits about 570 kilometers (km) above the surface of earth, whereas Webb will be 1.5 million kilometers (km) away at the second Lagrange (L2) point.

Since Webb is placed at higher altitude than Hubble, it will obviously be covering larger area and larger light collecting area. Because of the larger light-collecting region, Webb can view further back in time than Hubble.

Difference In Timeline Hubble Vs James Webb

In April 1990, Hubble was launched into low-Earth orbit. The telescope has taken magnificent photographs that have helped us comprehend how the universe looks for more than three decades.

On the other hand, the James Webb Telescope, which became operational in December 2021, is going to observe objects that are 10-100 times fainter than Hubble.

The Monkey Head Nebula, a star-forming region, was photographed by the Hubble Space Telescope in infrared and visible light. A jet of material from a newly emerging star can be seen in one of the pillars, just above and left of the center, in the right-hand image.

Several galaxies that are substantially farther distant, their dust and gas columns are also seen in infrared photos.

Klaus Pontoppidan remarked during a news conference before the launch that Webb’s images will be superior to Hubble’s. Due to the wavelength changes, he also stated that the pictures would be “different.”

In addition, Webb is built to detect infrared light, resulting in unexpected and beautiful photos. On the other hand, Hubble can see light in both the optical and ultraviolet spectrums.

Difference In The Orbits Hubble Vs James Webb

The Earth is 150 million kilometres away from the Sun, whereas the moon orbits it at 384,500 kilometers. The Hubble Space Telescope orbits at a height of 570 kilometres above the surface of Earth whereas Webb will not orbit the Earth; instead, it will sit 1.5 million kilometers away at the L2 Lagrange point between the Earth and the Sun!

Difference In Wavelengths Of Hubble Vs Webb

The Hubble Space Telescope is 340 miles away from the Earth, while the Webb Space Telescope is a million miles away at L2 Lagrange point. So, Webb must be cooler than Hubble in order to capture faint infrared wavelengths of light. As a result, Webb needs protection from the Sun, Earth, and Moon’s infrared radiation.

Webb will use four scientific instruments to collect images and spectra of celestial objects, predominantly in the infrared. These sensors will have a wavelength range of 0.6 to 28 micrometers (or “microns”; 1 micron is 1.0 x 10-6 meters). Infrared wavelengths range from 0.75 microns to a few hundred microns in the electromagnetic spectrum.

This means Webb’s equipment will primarily function in the infrared range of the electromagnetic spectrum, with some visual capacity (namely in the red and yellow portions of the visible spectrum).

Difference In Size Hubble Vs James Webb

Webb will have a primary mirror with a diameter of around 6.5 meters, which will provide it with a much larger collecting area than current space telescope reflectors.

With a diameter of approximately 2.4 meters and a collecting surface area of only 4.5 m2, Hubble’s mirror is significantly smaller, giving Webb around 6.25 times more collecting area.

Webb will have a far larger field of vision (more than 15 times that of Hubble’s NICMOS camera) and much better spatial resolution than the Spitzer Space Telescope’s infrared sensor.

Difference In Size Of The Sunshield

Webb’s solar shield is 22 by 12 meters in size (69.5 ft x 46.5 ft). It’s almost the same size as a 737 plane. The size of a tennis court is comparable to that of a sunscreen.

Passing Through South Atlantic Anomaly Webb VS Hubble

The South Atlantic Anomaly is a minor blip in the Earth’s magnetic field that has the potential to disrupt satellites. About 15% of the time, Hubble travels across this weak region. Webb, on the other hand, will not come into contact with this abnormality.

Hubble was propelled into orbit by a space shuttle, which is in Earth’s orbit. Webb will be launched on an Ariane 5 rocket and will not be able to be serviced by the space shuttle because it will not be in Earth orbit.

How Far The Telescopes Can Look, Hubble VS Webb

Webb is expected to see light from the universe’s first stars and galaxies by going beyond Hubble’s range, revealing how the stars looked 13.7 billion years ago.

At the L2 point, Webb’s solar shield will filter light from the Sun, Earth, and Moon. Webb will be able to stay cool, which is important for an infrared telescope.

Webb will orbit the Sun in the same way that the Earth does but will stay in the same position in relation to the Earth and the Sun. Rather than remaining immobile at a given location, satellites orbit around the L2 point, as indicated in the diagram.

Since light takes times to travel to the telescope mirror, the farther away an object is, the further back in time we are looking.

The Hubble Space Telescope can see “baby galaxies,” and the Webb Telescope will be able to see them as well. Webb will be able to see the first galaxies because it is an infrared telescope. The universe continues to expand. When discussing distant objects, Einstein’s General Relativity comes into play.

It explains that as the cosmos expands, the space between objects expands as well, causing objects to drift apart. Furthermore, any light in that area will stretch, changing its wavelength to longer wavelengths.

Because infrared light reaches humans, it can make distant objects appear dull (or perhaps undetectable) at visible light wavelengths. These early galaxies can be studied with the Webb and other infrared telescopes.

Difference In Infrared Hubble VS Webb

According to the fact sheet, Hubble can see light with wavelengths ranging from 200 nanometers (nm) to 2.4 microns, but Webb’s range will be 600 nm to 28 microns. Visible light has wavelengths ranging from 700 to 400 nm.

Even though Webb primarily monitors infrared light, it will be able to see the red/orange part of the visible light spectrum. The gold coating on its mirrors absorbs visible blue light but reflects visible yellow and red light, which is detected.

There’s One More Competitor To Webb And That Is Herschel

The Herschel Space Observatory, an infrared telescope orbiting the L2 point, was built by the European Space Agency.

Herschel’s wavelength range is 60 to 500 microns, while Webb’s is 0.6 to 28.5 microns. Webb’s mirror is 6.5 meters long, while Herschel’s is only 3.5 meters.

Herschel’s infrared image of the Andromeda Galaxy (M31) (orange) is superposed on top of an X-ray image from XMM-Newton (blue).


It is incorrect to pick between the Hubble Space Telescope and the James Webb Space Telescope and conclude which one is better because they are not same in nature, work, or how they view the enormous cosmos.

“Comparing Hubble to Webb is like wondering if your second child will love you as much as your first,” said Susan Mullally, deputy project scientist for Webb at the Space Telescope Science Institute in Baltimore.

Astronauts prepared for an emergency spacewalk, but Earth’s directives freed the panel. After only a few weeks, Hubble’s cloudy eyesight was found. Three years later, spacewalking astronauts fixed the problem.

Webb is currently at 1 million miles (1.6 million kilometers) from Earth and out of reach of astronauts.If the foldout mirror and sun shield on Webb, which is larger and more sophisticated than Hubble, become tangled, the spacecraft will be destroyed.

“Hubble will be remembered for providing spectacular views of our universe as well as collecting vital data for scientists but Webb will provides us new and unique perspectives of places we’ve never been able to visit.”

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