The Future of Looking Into the Past

Stars have been used in myth and legend as long as people have told stories and in navigation as long as people have traveled. In order to learn about the past of humanity and the planet, we dig, drill, and dive. To learn about the past of the solar system and the universe, we look, listen, and launch.

How far back we look determines the scale and tools we use. If we are looking into the recent past that’s human time. We can use lifetimes or generations to reckon with how long-ago events took place. Much more than 10,000 years ago and we get into Geologic time. Drilling for samples and examining them under a microscope are common methods with this scale. Determining the age of planets, pulsars, and the universe itself is the domain of Cosmic time.

It’s a real mind fuck, but we cannot see things as they are. As I write this there is an imperceptible delay between depressing a key on my keyboard and the corresponding letter appearing on my screen. The three feet from my computer to my face is laughable so it appears instantaneous. Scaled up to the 93 million and change miles between our Sun and Earth, the delay becomes eight minutes. Light from our nearest stellar neighbor, Alpha Centauri A, is over 4 years “old” when it reaches us.

Astronomers from Aristarchus of Samos in the 2nd century BCE, to Nicolas Copernicus in the 1440s had only the naked eye as observational tools. The invention of telescopes in the 1610s changed the game. A little-known Italian, Galileo Galilei, observed Jupiter’s moons and Saturn’s rings with his fledgling invention. Groundbreaking as Galileo’s refracting telescopes were, they were difficult to make and finnicky. About 60 years later Newton created the first reflecting telescopes. I read a lot of technical mumbo-jumbo on why but would only butcher an explanation of the differences. TL;DR, reflecting telescopes are way better.

A few hundred years of experimentation and refinement later optical telescopes are much more powerful and sophisticated. To illustrate this point, telescopes an order of magnitude more powerful than Galileo or Newton ever used are commercially available and relatively affordable.  At this point specialized telescopes, on Earth and in space, observe the huge swaths of the EM-spectrum that simply aren’t visible to humans.

Terrestrial telescopes have to deal with a lot of interference. Chiefly light pollution from cities and atmospheric scattering. There are two ways to get richer data. Figuring out what to do to reduce interference is pretty straight forward, go where there is less. Simple enough, isolated places far away from cities.  It was a logistical pain in the ass but now telescopes get built on mountains in Hawaii or the middle of the Chilean desert. The atmosphere still wreaks havoc on observational data from billions of light-years away. To get rid of the atmospheric shenanigans, go where there is no atmosphere. Thanks to the Cold War and Space Race, physicists and rocket scientists know how to put things, including but not limited to telescopes, in specific spots in space.

Hopefully you’re still with me. Here comes why I spent the last 500 words talking about light delay and atmospheric interference. The Hubble Space Telescope and its fellow space observatories have been as revolutionary to astronomy as Galileo’s first telescopes. With it we can look further back, and increasingly closer, toward the formation of the universe. Some of the most beautiful pictures are composite images from different telescopes observing different EM waves. The telescopes currently in orbit are, relatively speaking, antiques. The James Webb Space Telescope, part of the next generation of space observatories, will make Hubble look like one of Galileo’s first attempts. Hubble is great, it’s 1080p. The JWST is 8K.  

The Hubble Ultra Deep Field is my single favorite image. MRIs are fascinating and my cousin’s babies are adorable, but they are a distant, distant second. One of the best parts is that those dots aren’t stars. Each of them is an individual galaxy. If that is what 1080p got me, I am giddy to see what it looks like in 8K. 

I give the James Webb Space Telescope, sight unseen, four and a half stars.

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Special thanks to Hank Green for introducing me to the JWST in a 2011 vlogbrothers video. Thanks also to the team that puts together SciShow Space, their work was an invaluable resource.