Explanation: comparison of two space telescopes


On December 25, the new James Webb Space Telescope was launched into space from South America aboard a European Ariane 5 rocket.

“[countdown from 10 in French, continued in English] To take off! Of tropical Rainforest at the edge of time itself, James Webb begins a journey to the birth of the universe.

NASA and the European Space Agency’s Hubble Telescope has been circling the Earth for almost 32 years. Webb is widely regarded as the next generation telescope.

Experts recently spoke with The Associated Press about the differences between the two telescopes. But by talking to scientists about astronomy, do not ask them to choose a favorite.

“Comparing Hubble and Webb is like asking if you love your second child as much as your first,” said Susan Mullally. She is a scientific assistant for Webb’s project at the Space Telescope Science Institute in Baltimore, Maryland in the United States.

“Hubble will always be loved for its inspiring images of our universe and will continue to collect important data for astronomers. But the Webb telescope, Mullally adds, will allow us to see places in the universe never before seen. The Webb telescope is bigger and 100 times more powerful than Hubble.

In 1990, Hubble found itself in orbit inside NASA’s Space Shuttle Discovery. For Webb, the NASA website explains that it was helpful for the launch to be near the equator because “… twirl of the Earth can help give an extra boost.

Location and problems in space

Hubble turns 530 kilometers above us. This distance was determined by the capabilities of the NASA space shuttles. When problems arose on Hubble, ground control specialists and astronauts were able to resolve them.

However, this will not be the case with Webb. Webb is heading to a much more distant location, 1.6 million kilometers away. If he has any problems, it will be on its own.

All the light we see

Webb should record the light of the first stars in the universe and galaxies. This is beyond the capabilities of Hubble. This light will show us what the original stars looked like 13.7 billion years ago.

Hubble looked back 13.4 billion years. Astronomers want to close this 300-million-year-old hole with Webb. This will come closer and closer to the Big Bang, the time when the universe formed 13.8 billion years ago.

Infrared vision

Hubble sees what we see: visible light.

Webb a infrared vision, so that he can see the light that is invisible to Hubble. He can see through clouds of space dust. The shortest visible and ultraviolet the light emitted by the first stars and galaxies stretched as the universe grew. So Webb will see them in their infrared form, which expands and gives off heat.

Webb detectors need to operate at minus 240 degrees Celsius. To stay that cold, Webb carries an “umbrella” the size of a tennis court. Between each of the five layers of the sunshade is a hole so that the heat can escape through the sides.

Larger mirror

To see the first stars in the universe, Webb needs the largest mirror never launched for astronomy.

The Webb mirror measures over 6.5 meters. Hubble is 2.4 meters in diameter. However, Webb’s mirror is lighter because it is made of beryllium, a strong but light metal.

Production and costs

Hubble and Webb have some things in common: Production of both is years behind schedule and over budget.

NASA’s cost to Hubble from its development in the 1970s until now is around $ 16 billion, adjusted for inflation. This does not include all shuttle flights for launch and repairs.

The price to pay for Webb is estimated at $ 10 billion. This includes the first five years of operation. The European Space Agency covers the launch costs.

I am Anna Matteo.

The Associated Press’s Department of Health and Science receives support from the Department of Science Education at Howard Hughes Medical Institute. The AP is solely responsible for all content.


Words in this story

tropical – adj. or occurring in the tropics

astronomy – not. the scientific study of stars, planets and other objects in space: astronomer – not. a person who is a specialist in astronomy

inspiring adj. that arouses fear or wonder

twirl – v. turning around or causing someone or something to turn around repeatedly

galaxy – not. one of the very large groups of stars and associated matter found throughout the universe

infrared – adj. producing or using rays of light that are invisible and longer than rays producing red light

vision – not. the act or the power to see

ultraviolet – adj. used to describe rays of light which cannot be seen and which are slightly shorter than rays of purple light

detector – not. a device that can tell if a substance or object is present

mirror – not. a piece of glass that reflects images


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