Sunday, 28 August 2022

The James Webb Space Telescope is astronomy's shiny new toy, but the Hubble Space Telescope isn't old news — it's at its scientific peak

The Hubble Space Telescope launched in 1990 and has provided humanity a front-row seat to the cosmos for over three decades.
The Hubble Space Telescope launched in 1990 and has provided humanity a front-row seat to the cosmos for more than three decades.
  • Since its launch in 1990, the Hubble Space Telescope has made revolutionary achievements in astronomy.
  • The new James Webb Space Telescope is popular, but Hubble has skills, like capturing visible and ultraviolet light, that Webb doesn't.
  • The two telescopes will team up to study the cosmos in even greater detail. 

For three decades, the Hubble Space Telescope has delivered breathtaking cosmic views.

As the world raves about NASA's new James Webb Space Telescope, aging Hubble continues to be an astronomical workhorse, providing important observations of the universe, while Webb soaks up the spotlight.

But as a pair, the telescopes are even more powerful than they are alone. Together, the space-based telescopes will give astronomers a more complete view and understanding of galaxies, stars, and planets than ever before.

"The Webb Space Telescope is good news for astronomy, and good news for the Hubble Space Telescope as well, since Webb and Hubble enhance and complement each other's unique capabilities," Jennifer Wiseman, senior project scientist for the Hubble Space Telescope at NASA's Goddard Space Flight Center, told Insider.

"Hubble's science return is expected to be strong, and even enhanced throughout this decade as Webb and Hubble unveil the universe together."

Through Hubble's looking glass

Hubble being deployed from Discovery in 1990.
Hubble being deployed from Discovery in 1990.

Since Galileo Galilei constructed his telescope in 1609, astronomers have turned these tools to the sky. Astronomers developed these instruments significantly over time, allowing them to peer even deeper into the universe.

But their observations were constrained by Earth's atmosphere, which absorbs light before it reaches ground-based telescopes. Enter space-based telescopes. By sitting high above the distortion of Earth's atmosphere and away from light-polluted cities, observatories like Hubble provide, as NASA puts it, "an unobstructed view of the universe." 

Hubble launched on the space shuttle Discovery on April 24, 1990. Though it was originally scheduled for only 15 years of service, it still zips through space about 340 miles above Earth's surface, circling the planet every 97 minutes.

"Hubble is in good technical condition, even 32 years after its launch, with a strong suite of science instruments on board," Wiseman said.

Eagle_nebula_pillars
The Pillars of Creation in the Eagle Nebula, taken by the Hubble Space Telescope in 1995.

Over the years, Hubble's images have played a significant part in our understanding of the universe. It provided evidence of supermassive black holes at the centers of galaxies and measurement of the expansion rate of the universe. Hubble also helped discover and characterize the mysterious dark energy causing that expansion by pulling galaxies apart. Among its most iconic achievements is its Pillars of Creation image, taken in 1995, which shows newly formed stars glowing in the Eagle Nebula.

And Hubble's still taking stunning pictures, even after Webb began delivering images from its scientific observations in July. Recently, Hubble snapped an image of star-studded NGC 6540, a globular cluster in the constellation Sagittarius. 

A globular cluster NGC 6540 in the constellation Sagittarius, which was captured by the Hubble Space Telescope.
A globular cluster NGC 6540 in the constellation Sagittarius, which was captured by the Hubble Space Telescope.

Webb's infrared gaze

Both Webb and Hubble are space-based telescopes, but they differ in many ways. Hubble sees ultraviolet light, visible light, and a small slice of infrared, while Webb will primarily look at the universe in infrared.

Webb — which is 100 times more powerful than Hubble — will be able to peer at objects whose light was emitted more than 13.5 billion years ago, which Hubble can't see. This is because this light has been shifted into the infrared wavelengths that Webb is specifically designed to detect. 

But because Webb has been designed this way, it will also miss celestial objects in the visible and ultraviolet light that Hubble can see.

"In fact, Hubble is the only major class observatory that can access UV wavelengths," Wiseman said.

A collage shows pictures from the Hubble and the James Webb space telescopes side by side
A deep field image from the Hubble space telescope, left, and a deep field image from the James Webb Space Telescope, right.

A telescopic twosome

While Webb has been referred to as Hubble's successor, the two space-based observatories will be teaming up to unveil the universe together.

Wiseman points to how they'll provide insights into how stars are born within the clouds of cosmic dust and scattered throughout most galaxies. "Hubble, for example, can detect and analyze in detail the hot blue and UV light blazing from star-forming nebulae in nearby galaxies," Wiseman said, adding, "That can be compared to the vigor of star formation in the early universe as detected with Webb."

The two space-based telescopes will also combine their gazes to peer at the atmospheres of other worlds, looking for signs they might harbor life. 

Astronomers typically look for the ingredients that sustain earthly life — liquid water, a continuous source of energy, carbon, and other elements — when hunting for life-supporting planets. In 2001, Hubble made the first direct measurement of an exoplanet's atmosphere. 

"In our own galaxy, the understanding of planets within and beyond our own solar system will be greatly enhanced with the Webb and Hubble combo," Wiseman said, adding, "Signatures of water, methane, and other atmospheric constituents will be identified using the combined spectroscopic capabilities of Webb and Hubble."

Artist's impression of a planet orbits a yellow, Sun-like star called HD 209458 — the first direct detection of the atmosphere of a planet orbiting a star outside our solar system.
In 2001, Hubble made the first direct detection of an atmosphere of world orbiting a star beyond our solar system. Artist's impression of the planet, which orbits a star called HD 209458.

And though Webb may be seen as the shiny new toy in astronomy, Hubble's unique capabilities in capturing visible and ultraviolet light still make it a sought-after tool for understanding the cosmos. "Hubble is actually at its peak scientific performance now," Wiseman said. That's thanks to a team of NASA technical experts on the ground who monitor and quickly address any technical challenges that arise, she added.

"The number of proposals from scientists around the world who want to use Hubble has risen to over 1,000 per year, with only the top fraction of these selected for actual observations," Wiseman said, adding, "Many of these complement proposed Webb observations."

Read the original article on Business Insider


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