NASA’s Spitzer Space Telescope Will Soon Retire. What Will Take Its Place?
On January 30, NASA plans to close down its Spitzer Space Telescope, which has offered key observations of the universe for the previous 16 years. Spitzer gave essential infrared knowledge to scientists, and they’re now seeking to different telescopes to fill the gaps.
Spitzer observes mild within the infrared portion of the spectrum, which is mild at longer wavelengths than what our eyes see. In the near-infrared (wavelengths closest to seen mild), mud turns into clear, letting astronomers peek into star-forming areas of galaxies or research cooler stars. At barely longer wavelengths, infrared mild can be utilized to review planetary techniques round different stars and the disks that type them. At the longest infrared wavelengths, astronomers research cool clouds of mud and fuel, and even peer into the hearts of galaxies wrapped in dusty clouds.
Launched in 2003, Spitzer’s mission had two phases. Initially Spitzer’s devices, cooled with liquid helium to –459 levels Fahrenheit (–273 levels Celsius), noticed mild with wavelengths from three to 160 micrometers throughout its chilly mission. In 2009, the telescope ran out of coolant, starting its “warm” mission. Spitzer might now not observe longer wavelengths however continued observing at brief wavelengths: three.6 and Four.5 micrometers.
But Spitzer just isn’t the one house telescope in operation immediately, and present and future telescopes do have infrared-sensing capabilities. Here’s what astronomers may have of their infrared toolbox as soon as Spitzer has been shut down.
The Hubble Space Telescope is famously considered one of astronomy’s greatest workhorse telescopes. It does have the flexibility to look at infrared mild, however that functionality is proscribed. Hubble can detect infrared mild solely between zero.eight and a pair of.5 micrometers, which doesn’t overlap with Spitzer’s present or previous capabilities. So, whereas Hubble can definitely complement Spitzer and different infrared observations, it can’t change Spitzer’s skill to chart the infrared sky.
NASA’s Wide-field Infrared Survey Explorer (WISE) house telescope observes the universe with a zero.Four-meter mirror at wavelengths from three.Four to 22 micrometers. Deactivated in 2011, the telescope was reactivated in 2013 as NEOWISE. Today, it’s used to look at near-Earth objects, akin to asteroids and comets. The telescope stays a helpful asset to infrared astronomy, however it doesn’t look past our personal photo voltaic system, specializing in science solely near dwelling.
The James Webb Space Telescope (JWST) is NASA’s subsequent infrared house observatory. But JWST continues to be a little bit over a yr from its present deliberate launch date of March 2021. JWST will observe from zero.6 to 28 micrometers, which ranges from the yellow-gold finish of the seen spectrum to what astronomers name the mid-infrared. That covers the 2 wavelengths presently noticed with Spitzer’s heat mission however doesn’t prolong as deeply into the far infrared as Spitzer as soon as might. (The definitions of mid- and much infrared can range, however most astronomers outline the far infrared as wavelengths between about 25 and 350 micrometers.)
That means whereas JWST can change Spitzer for astronomers who observe, say, stellar nurseries, cool stars, exoplanets, and the disks round younger stars, it might’t utterly change Spitzer’s skill throughout its chilly mission to look at very chilly mud or the facilities of some galaxies.
NASA’s proposed Wide Field Infrared Survey Telescope (WFIRST) has been on and off the chopping block in recent times. The telescope, if launched as deliberate within the mid-2020s, will use a 2.Four-meter mirror to look at near-infrared mild between zero.48 and a pair of micrometers. That places it extra in keeping with the wavelengths Hubble can see, and under Spitzer’s wavelength vary.
WFIRST’s actual declare to fame is true there in its title. It may have a large area of view capable of see 100 instances extra space of the sky than Hubble in a single shot, however with the identical picture high quality. That will dramatically enhance the quantity of science it might do; and whereas it gained’t take a look at the identical wavelengths as Spitzer, its near-infrared vary is suited to many initiatives together with those who depend up galaxies, supernovae, and exoplanets.
So, are infrared astronomers simply out of luck? After all, infrared astronomy is basically unimaginable from the bottom as a result of the water in Earth’s environment blocks most infrared mild. That’s why telescopes are launched into house, the place they get a transparent view.
But, it seems, you don’t have to go all the way in which to house to see the universe in infrared. The Stratospheric Observatory For Infrared Astronomy (SOFIA) consists of a telescope mounted inside a modified Boeing 747SP plane that flies between 37,000 and 45,000 ft (11,300 to 13,700 m). That places it above 99 % of the water in Earth’s environment. SOFIA observes mild between zero.35 and 655 micrometers, which covers your entire vary of Spitzer’s functionality — each heat and chilly — in addition to JWST’s and extra.
SOFIA is an observatory aboard an plane. It can fly above many of the water in Earth’s environment to look at infrared mild. (Credit: NASA/Jim Ross)
In all, SOFIA is the very best candidate to exchange Spitzer in its entirety. Even higher, SOFIA’s mirror is bigger than Spitzer’s (2.5 m versus zero.85 m), so it might provide higher picture high quality in some instances than the retiring telescope. And SOFIA’s telescope could be repaired and upgraded as wanted, extending each its lifetime and its capabilities.
But there are tradeoffs. SOFIA sometimes makes 10-hour flights, however it should nonetheless land for refueling and different upkeep. Because of Earth’s rotation, it might solely observe the identical area of sky for a most of some hours at a time. The plane additionally takes time to get from one location to a different and might not be in the precise place to look at short-lived occasions. And lastly, SOFIA is above most — however not all — of Earth’s environment, so in some instances, observations are nonetheless restricted by the layers above it.
The Spitzer Space Telescope is a really distinctive and memorable telescope that has helped astronomers uncover clues about a lot of our universe, from the primary stars and black holes to planets round close by stars. Although observing the infrared sky with out Spitzer could look barely completely different sooner or later, astronomers nonetheless have instruments to proceed peering deep into the universe.