The Incredible Telescope That Lets Us Travel Back in Time

Time question has ever been a phantasy humanity loves to deliberation about. What was it similar successful the distant past? How person things changed, what would it beryllium similar if you were there? Time question is not physically possible, but acknowledgment to the James Webb Space Telescope, we tin look backmost successful clip arsenic if it were.

Telescopes Allow Visual Time Travel

It whitethorn dependable similar subject fiction, but I'm not exaggerating erstwhile I accidental that telescopes let you to look backmost successful time. The James Webb Space Telescope (JWST), Hubble, and adjacent the backyard telescopes you tin buy each let you to spot backmost into the past to immoderate extent. In fact, the precise enactment of seeing thing is looking backmost successful time, though erstwhile it comes to the bare eye, it's usually not to immoderate grade important capable to matter.

To recognize what I mean, let's speech astir airy for a minute.

Everything You See Is from the Past

The mode humans spot with their eyes is complicated. In the simplest terms, airy travels from an entity into our eyes, wherever it is converted into an electrochemical signal. The awesome is past sent to the encephalon and processed, allowing america to spot things. Here's the thing—light takes clip to travel. It doesn't often look similar it present connected Earth, but that's due to the fact that airy travels astatine an incredibly speedy 186,000 miles per hour. Even astatine utmost distances connected Earth, airy volition question from 1 constituent to the adjacent precise quickly. In your day-to-day life, the velocity of beingness usually feels astir instantaneous.

It's not instant, however. Nearly instant, but not instant. Because it takes immoderate clip for airy to travel, adjacent if it's down to nanoseconds, everything you spot is technically successful the past, not arsenic it is close this moment. It's insignificant present connected Earth but becomes overmuch much important to instrumentality into information arsenic the region successful question grows larger. Naturally, this means the velocity of airy is overmuch much noticeable successful space.

For example, it takes airy from the Sun astir 8 minutes to scope Earth. This means you are ever seeing the Sun arsenic it existed 8 minutes ago, not arsenic it is close now. If our prima exploded right astatine this moment, you would not beryllium capable to spot it for the adjacent 8 minutes, due to the fact that that's however agelong it would instrumentality the airy from that infinitesimal to scope your eyes and springiness you a caller visual. It's benignant of scary, honestly.

At immoderate rate, the velocity of airy dictates what we are seeing erstwhile we observe space. The farther distant an entity is, the longer it takes for airy from that entity to scope us, and that means we are seeing those objects arsenic they were successful the past, not arsenic they are close now. Alpha Centauri is 4 airy years away, truthful we are ever seeing it arsenic it was 4 years ago. The North Star is 446 airy years away, truthful for each we know, it could person gone supernova 3 100 years ago, and we won't adjacent cognize it until 146 years from now.

This rule is wherefore incredibly almighty telescopes similar the JWST alteration america to spot into the distant past. So far, even, that we whitethorn beryllium capable to spot millions of years farther into the past than Hubble was susceptible of.

The James Webb Space Telescope

For a agelong time, Hubble was the astir almighty optical scope successful humanity's arsenal. Because it was monolithic and capable to look into abstraction without obstruction from Earth's atmosphere, Hubble was capable to spot incredibly acold into space, observing celestial objects billions of airy years away, specified arsenic galaxies and nebulae, and providing captious grounds supporting the beingness of black holes. The JWST is Hubble's companion and volition let scientists to spot adjacent further backmost acknowledgment to a fewer cardinal features.

First, JWST is overmuch bigger than Hubble. Put simply, both Hubble and the JWST are reflecting telescopes that usage mirrors to cod and crook airy into their reflection instruments. The JWST has a overmuch bigger superior reflector than Hubble—21.3 feet compared to conscionable 7.9 feet. That's much than six times the airy collecting country erstwhile moving with the secondary and tertiary mirrors.

Here's wherefore this allows america to spot further into abstraction than Hubble does. As you whitethorn know, airy is portion of thing called the electromagnetic spectrum, and it travels successful a wave. Since the beingness is expanding, the question gets stretched retired arsenic it travels done space. As objects determination distant from us, bluish airy turns to green, greenish airy turns to red, and reddish airy shifts into the infrared.

Under mean circumstances, quality eyes cannot spot infrared light, but infrared images tin beryllium captured by definite instruments. The airy of immensely distant objects is successful the infrared spectrum by the clip it reaches Earth, and it's incredibly faint. Hubble tin observe immoderate of these, but not precise many. The JWST, connected the different hand, tin observe a overmuch broader scope of infrared airy than Hubble can, acknowledgment to its bigger, gold-plated reflector and peculiar instruments.

This means the JWST volition beryllium capable to prime up airy that is excessively faint for Hubble to adjacent identify. In fact, the JWST tin spot objects up to a 100 times fainter than the faintest objects Hubble tin see. The elephantine reflector allows the JWST to spot those objects astatine a akin solution to Hubble, since resolution—the level of discernible detail—is inversely proportional to reflector size and proportional to the wavelength of the observed light.

Furthermore, infrared airy cuts done particulate and different obfuscating worldly that whitethorn beryllium betwixt the JWST and an entity it's trying to observe, meaning it'll beryllium capable to get clearer images of immoderate objects than Hubble can. But the solution of the representation the JWST tin spot is really the aforesaid arsenic Hubble overall.

Is the James Webb Space Telescope Replacing Hubble?

So far, it whitethorn look similar the JWST is conscionable superior to Hubble successful each way, similar a newer exemplary that should regenerate the aged one. This is not the case. Hubble is old, but it's not being replaced by the JWST. That's due to the fact that Hubble really sees immoderate things that the JWST doesn't see. JWST sees chiefly infrared light. However, it's not really seeing overmuch disposable oregon ultraviolet light—at least, not arsenic overmuch arsenic Hubble.

This means that the 2 telescopes volition champion service arsenic a pair, with their combined specialties allowing america to spot celestial objects crossed a wide spectrum. Admittedly, determination volition beryllium immoderate objects that are truthful distant that Hubble won't beryllium capable to observe them astatine all, and the JWST volition person to observe those objects connected its own. Even so, the JWST is not replacing Hubble, it's simply providing a caller mode to observe the cosmos.

Witnessing the Birth of the Universe

The JWST is highly powerful, and immoderate radical person been led to judge that it whitethorn beryllium capable to spot the root of the universe, specifically, the Big Bang. While this is true, successful a way, it's besides a spot misleading. Here's the thing—you can't spot the Big Bang.

It's a communal misconception that the Big Bang was immoderate benignant of explosion, with an epicenter that the known beingness is rushing distant from, but this isn't existent astatine all. The Big Bang happened everyplace each astatine once, astatine a peculiar time, but not successful a circumstantial carnal place. The Big Bang refers to the opening of the universe's expansion, not the existent instauration of substance itself. It's each beauteous complicated, but the constituent is that the JWST cannot spot the Big Bang.

What it can see volition beryllium the archetypal objects that formed erstwhile the beingness started to chill down aft the Big Bang. The JWST is designed to spot however the precise archetypal stars and galaxies were formed successful the universe. The beingness existed earlier immoderate stars oregon galaxies formed, for millions of years even, but that has already been "seen" by precise antithetic tools, specified arsenic Cosmic Background Explorer (COBE), the Wilkinson Microwave Anisotropy Probe (WMAP), and Planck.

So really, the JWST isn't intended to spot the existent "birth" of the universe. It's designed to spot the instauration of the earliest objects successful the universe, which is rather a large difference. We've witnessed the clip earlier those progenitor stars and galaxies and the clip aft them, but we haven't really seen the clip play successful which they formed.

As for wherefore scientists privation to spot that, it's simple. They're curious! The chemic elements required for beingness were archetypal produced by the precise archetypal procreation of stars. Humanity lone exists due to the fact that those stars formed, and scientists person nary thought however those stars formed exactly. Some radical conscionable truly privation to cognize however we each got here, the infinitesimal that allowed our satellite and our taxon to adjacent exist. Curiosity is crushed capable for science!

---

Ultimately, the JWST is "just" a really, truly large telescope. The biggest humanity has ever made, successful fact. With it, scientists volition beryllium capable to "see" objects much distant than Hubble was ever susceptible of detecting, which means humanity volition beryllium capable to survey celestial objects successful the distant past of the universe. With this power, we whitethorn conscionable beryllium capable to spot however the precise archetypal stars and galaxies formed in the universe, and by extension, however Earth and humanity came to be.