Written by Daniel Ben
Humanity, in many ways, has always been connected to the night sky.
As nomadic hunter-gatherers, the stars had been a directional signpost. Agricultural societies treated it as a reminder of the seasons and when to plant certain crops, when to harvest, and when to till the soil to prepare for the next cycle of food production.
Sixty years ago, we had our first intimate contact with the stars when Yuri Gagarin had been to space for the first time. Fifty-two years ago, Apollo 11 and the famous step for mankind was celebrated. Forty-four years ago, the golden record of Voyager 1 was sent to space, an outstretched hand saying hello to the void.
All it took to greet the night sky was to look up, though our salutations never received a reply. The more we get to know of the night sky, the more we learn of what we don’t know about our own universe.
The Hubble telescope once stared at an empty speck of space for ten consecutive days between December 18 and 28, 1995. Rendered out of the 342 frames taken was a myriad of distant galaxies. Dubbed the Hubble Deep Field (HDF), it showed us the classic spiral and elliptical shaped galaxies amid a variety of shapes and colors, a possible clue to understanding the evolution of the universe.
Extrapolating this tiny dot and the many galaxies it contains to the entirety of the night sky, one could estimate that there are more than 100 billion galaxies in the universe.
Distance
We have a delayed viewing of the sun.
Due to the finite speed of light, it takes 8 minutes and 20 seconds for the sun’s light to reach the Earth. The sun you see outside your window is the sun 8 minutes and 20 seconds ago.
Knowing this, you could say that photos like the HDF are time capsules of some sort. It contains galaxies billions of lightyears away from us, and if you look at the very back of the image, you can even see reddish galaxies that scientists believe could be examples of what the very first galaxies looked like.
The issue when observing light that comes from these distant stars is that due to the distance, we can’t really see them properly because the light has red-shifted into infrared, gone beneath the spectrum of visible light.
Visible light, radio, infrared, ultraviolet, and x-ray all belong to the same electromagnetic spectrum, after all. When dealing with distant celestial bodies, the light is literally stretched by the nature of the universe’s constant expansion. Think of something like a balloon’s plastic being stretched as it is blown.
We’ve long known that if we truly want to know of the origins of the universe and observe these first stars, we need a telescope capable of seeing in infrared. The James Webb Space Telescope does exactly that.
Telescope
Thirty years in the making and costing 9.7 billion USD or about 500.3 billion PHP, the James Webb launched on December 25, 2021.
Seeing in infrared, its instruments need to be at freezing temperatures of about -250 C because just the slightest heat could throw off its readings. It maintains this coolness by having a sunshield essentially protecting the telescope properly from heat. One side facing the sun would be scorching hot, while the telescope proper on the cool side will be able to make observations.
Even then, it still isn’t cool enough, so scientists have placed a cryocooler, a refrigerator of sorts where helium will travel along pipes and cool its instruments to the right temperature. Otherwise, the telescope could start observing its own ambient heat.
The telescope mirror itself is 6.5 meters across, neatly folded into hexagonal panels along with all other instruments to fit in the rocket. Once in space, these panels will begin unfolding with enough precision to take a hair’s width into account.
It is currently calibrating at the Sun-Earth’s second Lagrange point, four-times the moon’s distance, where it will orbit the Sun at enough a distance that it isn’t so easily obstructed by light and heat but is able to orbit the Sun at the same rate as Earth due to the gravitational pull of the planet.
It’s expected that it will become operational in May 2022, six months after its launch.
Purpose
We can see further than ever before, with enough clarity to detect a bee’s heat signature from the distance of the moon.
With this power, there are four things in particular that James Webb seeks to learn about: the early universe, how galaxies transform over time, a star’s life cycle and exoplanets on other solar systems.
Humans, like any other living thing on Earth, are made out of star stuff. Wanting to understand how this star stuff came about is a curiosity that does not need justification, and learning about any of these four topics would greatly enrich our understanding of our universe. To answers of cosmic beginnings, to the chemical compositions of other worlds, to learning enough of our place amid billions and billions of galaxies.
Perhaps, with the power of the James Webb Space Telescope, we can finally properly say hello to the universe.
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