Hubble and James Webb: What are the differences between space telescopes?


the space telescope james webb is currently a trend after the presentation of the first color images taken by the instrument. At the same time, the Hubble it also meets its goals, like when it showed space fireworks.

Both telescopes were promoted by NASA and the European Space Agency (ESA), while in the case of the James Webb, named after the remembered former administrator of the American agency, there is also participation of the European Space Agency. Canada (CSA).

Each one is being used for different missions and studies, and they do indeed have physical and technical differences. Next, we will explain them.

Launch, weight, size and position

The Hubble Space Telescope was launched on April 24, 1990 for the STS-31 mission. It weighs 11 tons and measures 13.2 meters long by 4.2 wide. The cost of it was 2,800 million dollars.

For its part, the James Webb was launched on December 25, 2021, a clearly more modern telescope. Its weight is 6.2 tons and it measures 21 meters long and 14 wide., almost like a tennis court. It is larger, but weighs less than Hubble. Its cost was 10,000 million dollars.

Regarding its position in orbit, Hubble is 600 kilometers from Earth, while James Webb is 1.5 million kilometers, exactly at the point called Lagrange 2.

Comparison of mirrors and field of vision

Hubble has a mirror of 2.4 meterswhich may look like a thumbnail next to the powerful mirror of the James Webb, 6.5 meters. The larger the mirror, the greater the distance that can be seen with the telescope.

The highlight of the Webb’s supermirror is that it is formed for 18 gold-coated beryllium pieces, each 132 centimeters in diameter.

Macarena García Marín, an ESA scientist, told ABC that these characteristics mean that “The Webb will be able to study the universe in much more detail.”

James Webb Space Telescope image

With respect to the field of view, that of James Webb will be significantly greater than that of the camera that Hubble has.

García Marín explained: “Compared to the diameter of the Moon, an individual Webb image would be about 7 to 15 times smaller. The spectral data, where the light breaks up, covers a much smaller region of the sky”.

This is the reason why most of the images from these telescopes are composites of several captures. Of course, the resolution of James Webb is much higher than that of Hubble.

Webb infrared vs. Hubble ultraviolet

The James Webb observes the universe in the infrared spectrumwhile the Hubble it does so from optical and ultraviolet wavelengths.

Webb can see what is happening behind large clouds of gas and dust where stars and planets are forming. Also, appreciate the perspective of the universe as it was 13.5 billion years ago, a thousand years older than Hubble.

Basically, the Webb can see the light that emanated from the first moments of the cosmos and observe the first generation of stars and galaxies.

Below is a comparative example of the Pillars of Creation. The one on the right is in infrared.

Repair and service life

The Hubble telescope has surprised all scientists and experts for its longevity: lIt has been running for more than 30 years, largely thanks to various adjustments and fixes.

The James Webb, meanwhile, would have a useful life of five yearsbut space agencies expect it to be in orbit for at least 10 years.

Why will Webb’s activity last less than Hubble’s? By its location. Being further from Earth, it is more complicated to send a mission to repair it. In fact, future fixes for the space telescope are off the table.

While James Webb can provide us with higher resolution images, its time in orbit will be shorter compared to the old but durable Hubble. Space agencies will likely replace the Webb in the future.

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