Do people like threads here? I guess we'll find out!
Between meetings today I thought I'd talk about #NASA #JWST and all the exciting #science we can expect from it starting in a few months!
(Yes, I made this travel mug ❤️)
#SciComm #Exoplanets #Astronomy #Astrophysics #Telescope #MastodonNewbie
A quick note: if you ask me what #JWST stands for I'll tell you it's the Just Wonderful Space Telescope
https://www.scientificamerican.com/article/nasa-needs-to-rename-the-james-webb-space-telescope/
Fun Fact #1: #JWST is the LARGEST space telescope ever built! It's so big that the mirrors were folded up to fit in the #ESA #Ariane5 #Rocket that launched it last Christmas
(Yes, this diagram of me standing next to the Hubble and JWST mirrors is to scale!)
Because it launched folded up, #JWST spent the first several weeks verrryyy carefully unfolding itself in space as it traveled to its orbit.
The scariest part was the sunshield tensioning! The sunshield is the pink/grey part and is used to keep the mirrors and instruments nice and cold so we can see the very faint heat from the early universe!
By now you might be wondering: Why is the telescope #gold?
The mirrors are actually made of Beryllium, which is a very strong and lightweight metal, and are coated in a very thin layer of gold. The total amount of gold on #JWST is only about the size of a marble!
Why gold? Gold is VERY efficient at reflecting infrared light! JWST is designed to search for this heat in the early universe
Unlike the #Hubble Space Telescope, #JWST is not orbiting Earth! Because it's designed to look for faint heat in the early universe, it has to be far away so that the Earth's heat doesn't overpower what it's observing!
JWST is orbiting a point in space called L2, a gravitationally stable point nearly a million miles beyond Earth.
In this gif, the sun is at the center, Earth is the large blue dot, and you can see JWST orbiting an empty point in space beyond Earth. This is not to scale!
Now while the benefits of being so far away from Earth allow us to look even further back into the earliest parts of the universe, it also means that #JWST isn't serviceable like #Hubble
Did you know that when Hubble launched its primary mirror was made wrong and we had to send a Shuttle mission up to service it and give it glasses? Unfortunately if something goes wrong with #JWST we can't send humans to fix it. #JWST is nearly a million miles away and further than the moon!
Luckily, because JWST needed to be folded up we actually don't have to worry about the mirrors being shaped wrong. Since it's broken into segments, each segment can move on its own to help align the telescope perfectly.
This is best demonstrated by this #Lego #JWST model that was submitted to lego ideas and is currently under review!
Each segment can move independently so it reflects light perfectly to the secondary mirror and back to the instruments.
@m7tlg It's a little harder for #JWST to last so long since we don't currently have the capabilities for a crewed or robotic servicing mission. Part of why #Hubble has survived so long is the upgrades!
The nominal lifetime was required to be at least 5 years, but it was fueled for at least 10 years. Most of that fuel was to get it out to L2, but it turns out the #Ariane5 #Rocket provided such a PERFECT launch that it saved JWST lots of fuel, so now the prediction is it has about 20 years!
@_astronoMay I'd never thought of the servicing side of it before, I suppose if #Hubble wasn't in orbit then it might've been a *bit* of a disaster after the initial 'teething' problem!
20 years for the #JWST is still amazing! Means it might still be operational as my toddler (currently obsessed with dinosaurs, rockets and cars - like me!) is at university!
Erin M. May, PhD
John | M7TLG