The Sundarban
January 30, 2026
5 min read
Add Us On GoogleAdd SciAmFinally these years, the Hubble Home Telescope is still superior
The frail Hubble observatory goes solid no subject its a long time in space and the advent of next-generation successors
By Phil Plait edited by Lee Billings
Two NASA astronauts accept as true with upgrades on the Hubble Home Telescope high above Earth right thru a neighborhood shuttle servicing mission, STS-109, in March of 2002.
NASA
On April 24, 1990, humanity launched a scientific revolution.
I mean “launched” literally: on that date the space shuttle Discovery roared into the sky with the Hubble Home Telescope nestled in its cargo bay. The telescope was as soon as on a mission destined to forever exchange our stumble on of the universe.
Hubble wasn’t the biggest telescope ever—its 2.4-meter focal point on is de facto regarded as small these days—but being above the atmosphere gave it superpowers. Our air boils and roils, blurring the views from ground-basically based completely instruments. It glows, too—dimly but enough to restrict how faint an object astronomers can stare. And third, our air absorbs most ultraviolet and infrared gentle, the set attention-grabbing things happen, cosmically speaking. Getting up, up and remote from all that atmosphere made Hubble one of the most principal telescopes ever built.
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And revolutionize astronomy it did. Hubble observed objects fainter than had ever been observed sooner than. The telescope homed in on how mercurial the universe expands, watched weather adjustments on the outer planets and proved that every huge galaxy has a supermassive murky gap at its coronary heart, comely to name three wonderful feats off the top of my head. The main breakthroughs and discoveries that got here out of this stunning machine are so a vogue of, truly, that even itemizing them here would possibly perchance be low (and also a chunk unhurried, if impossible extraordinary exploration can also ever be unhurried).
And but, no subject these successes, I stare a vogue of chatter online (and even in the news) seriously cavalierly pushing apart Hubble, asserting that NASA’s James Webb Home Telescope (JWST) is Hubble’s “substitute.” That’s not comely unfair; it’s incorrect.
JWST was as soon as by no approach supposed to supplant Hubble, and in actuality can’t, offered that it was as soon as designed for terribly an expansion of observations.
Hubble is optimized to appear the universe in viewed gentle, the form of sunshine we stare with our eyes. It could most likely also moreover detect some wavelengths into the ultraviolet and infrared, but Hubble can’t stare most of these parts of the spectrum. JWST detects infrared gentle at extraordinary longer wavelengths, the set an expansion of astrophysical processes dominate.
JWST is a extraordinary elevated telescope, lawful. It has a 6.5-meter-broad focal point on, so it collects about seven times as extraordinary gentle as Hubble. In fashioned, a bigger focal point on also approach greater decision, a bigger capability to peek aesthetic small print in an observation. Yet that also depends upon upon the wavelength observed, and in actuality, at their respective most attention-grabbing, Hubble beats out JWST by a smidgen! But that’s not truly the point; both are distinctive telescopes that are at the forefront of the form of observations they can every slay.
Determining Hubble’s energy in viewed gentle serves to underscore one key arena the set JWST’s infrared imaginative and prescient exceeds it: glimpsing the universe’s first galaxies.
Hubble’s deepest observations showed that there was as soon as an surprising richness of galaxies in the far-off universe, but the telescope has a restrict. The more far-off a galaxy is, the more redshifted its gentle turns into as the cosmic expansion sweeps the galaxy remote from us. In the future, the bulk of the galaxy’s gentle is emitted in infrared, the set Hubble can not stare it—but the set JWST sees keenly. Attributable to this the newer observatory has been so prolific in breaking distance files and giving us unparalleled views into the early universe.
There is an irony here. The notion for a neighborhood telescope was as soon as first proposed by astronomer Lyman Spitzer in 1946, and in the 1960s astronomer Nancy Grace Roman started advocating NASA to accomplish one—she later became identified as the “mother of Hubble,” and a neighborhood telescope deliberate for begin this 365 days is named after her. Delays and value range overruns plagued the Hubble project, on the other hand, and in the slay, it injure up costing better than $10 billion and launching extraordinary later than at the beginning deliberate. The same thing came about with JWST; at the begin proposed to stamp below $1 billion and begin by 2004, its closing stamp was as soon as also about $10 billion, and it didn’t shuffle up till 2021. In this attain, both telescopes maintain a identical historical previous.
Then again, from a an expansion of point of stumble on, their historical previous is amazingly an expansion of. Hubble launched with a incorrect focal point on, one comely a micron or two too flat at the edges—far not up to the thickness of a human hair but better than enough to ruinously blur the telescope’s imaginative and prescient. I be conscious these fuzzy years well: right thru my Ph.D. review, I spent pretty somewhat time working with instrument that mathematically corrected about a of Hubble’s out-of-focal point images. Fortunately, this allege was as soon as bypassed with the begin of corrective optics in 1993, and later instruments had built-in corrections to make obvious that observations had been centered.
Few of us at the present time appear to even be taught about that complicated time (there had been congressional hearings looking out into NASA’s mistake!), and heaps now focal point most attention-grabbing on Hubble’s success. And that’s aesthetic,
