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What this article is really arguing

Phil Plait’s point is not simply that the Hubble Space Telescope is beloved or historically important. The article argues something stronger: Hubble is still scientifically valuable, and it is a mistake to talk about the James Webb Space Telescope as if it has simply replaced it.

That claim matters because Hubble can seem old enough to be obsolete. It launched in April 1990, long before many of today’s astronomers began their careers, and it now shares the stage with a much newer and more powerful observatory. Yet the author insists that this way of framing the story misses how telescopes actually work. Scientific usefulness is not determined only by age or mirror size. It depends on what kinds of light an instrument can see, what observations it was built to make and how well it still performs those tasks.

Why Hubble changed astronomy so dramatically

The article starts by reminding the reader why Hubble was transformative in the first place. Its mirror was not especially large even at launch, and by current standards it is modest. What made it revolutionary was altitude. By operating above Earth’s atmosphere, Hubble escaped the turbulent air that blurs ground-based observations, the faint atmospheric glow that hides dim targets and the atmospheric absorption that blocks much of the ultraviolet and infrared spectrum.

That freedom gave astronomers a much sharper and darker window onto the cosmos. The article points to some of the telescope’s most famous accomplishments: refining the expansion rate of the universe, tracking weather on outer planets and helping to show that massive galaxies harbor supermassive black holes in their cores. Plait’s larger message is that Hubble was not just one successful instrument among many. It reset the scale of what space-based astronomy could do.

Why Webb is not Hubble’s replacement

The center of the article is a corrective to a common misunderstanding. Webb is bigger, newer and better at some jobs, but that does not make it Hubble’s all-purpose successor. The two telescopes were designed to answer different kinds of questions.

Hubble is strongest in visible light, with some ability to work in the ultraviolet and infrared. Webb is optimized for much longer infrared wavelengths. That difference is not a technical footnote. It determines what each telescope can see well. Hubble is still superb at visible-light imaging, and at its best it can even edge out Webb in resolution because resolution depends on wavelength as well as mirror size.

Webb’s real advantage comes when astronomers want to study the very early universe. As distant galaxies race away from us with cosmic expansion, their light gets stretched into the infrared. Hubble eventually runs out of reach there, whereas Webb can keep going. That is why Webb has been so effective at finding extremely distant galaxies and probing cosmic dawn. The article’s point is not that Webb is overhyped. It is that comparison only makes sense if one remembers that these telescopes are complementary, not interchangeable.

The near-failure that became a long success story

One of the best parts of the article is that it does not tell a smooth triumphalist story. Hubble began with a humiliating flaw: its mirror had been ground slightly wrong, enough to blur its vision badly. The error was tiny in everyday terms but disastrous for precision astronomy. Plait recalls working with software that tried to salvage those blurred images before astronauts installed corrective optics in 1993.

That repair is central to the telescope’s legacy. Hubble was not a perfect machine that simply worked forever. It became a success because engineers and astronauts kept improving it. Later servicing missions upgraded its instruments, solar panels and optical systems, which means the Hubble still operating today is in important ways better than the one that launched.

The author uses that history to draw a contrast with Webb. Webb had its own delays, overruns and complexity, but it also benefited from lessons learned during Hubble’s painful early years. In inflation-adjusted terms, and especially once Hubble’s shuttle servicing costs are counted, Webb even looks less extravagant than casual comparisons suggest. Hubble’s failures were not just embarrassing episodes. They helped teach NASA how to build the next generation more carefully.

Why Hubble still matters now

The article closes by arguing that longevity itself is part of Hubble’s achievement. Its original mission was supposed to last about 15 to 20 years. It is now in its 36th year and has made more than 1.7 million observations. That alone would make it remarkable, but the piece goes further: Hubble remains active science hardware, not merely a monument kept running for nostalgia.

Its aging gyroscopes are a real constraint, and the telescope is clearly in a late phase of life. But NASA engineers have kept it productive even with only one operating gyro. The broader lesson is that major observatories should be understood as part of a lineage. Hubble did not become irrelevant when Webb launched. Instead it helped make Webb possible, and future telescopes will inherit from both.

The takeaway

This article treats Hubble as a working observatory with a durable niche, not as a retired icon. Its historic importance came from putting a powerful telescope above the atmosphere and opening a much clearer view of the universe. Its current importance comes from the fact that visible-light astronomy in space still matters, and Webb cannot simply absorb that role.

The deeper theme is that scientific progress is usually additive. New instruments do not always erase the old ones. Sometimes they clarify what the old ones were best at all along. Hubble changed astronomy once by launching into orbit. It is still shaping astronomy now by continuing to observe, by having taught hard lessons to later missions and by proving that a great telescope can remain scientifically alive far longer than anyone first planned.