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29 Days of Astronomical Terror

2021-12-24 · explainer · Hank · 3:50 · watch on YouTube

Topic: Science & nature · mode: News analysis · tags: timely hook

On the eve of its Christmas launch, Hank explains why the James Webb Space Telescope must observe in infrared from a cold, shielded orbit, walks through the tense 29-day deployment timeline, and says curiosity is close to the root of being human.

What is said

The parts of the video and what is said in each (★ — how much it matters to the video).

00:00:00 — A Christmas Eve video for the Christmas Day launch; Hank's Webb video ten years ago; the big questions

  • ★★ Hank would not normally release a video on Christmas Eve, but people who worked for decades on one of the most exciting instruments ever built are launching it on Christmas Day. — 00:00:00 · Christmas
  • ★★ Hank made a video on this channel ten years ago about how amazing the James Webb Space Telescope would be, and now it is headed to space. — 00:00:00
  • ★★★ Hank calls the telescope an endeavour to answer some of the biggest human questions: how planets form, whether there is life elsewhere, how the universe works. — 00:00:00

00:00:29 — Why infrared, why the telescope must be so cold, the heat shield and the orbit

  • ★★ Hank explains Webb must see in infrared, impossible from the ground, mainly because the universe's expansion has stretched light from long ago and far away into the infrared. — 00:00:29
  • ★★ Since everything with heat emits infrared, a warm telescope's mirrors would swamp the faint light from exoplanets and the early universe, so it must be extremely cold and shielded from the Sun, Earth and Moon. — 00:00:58 · Earth
  • ★★ Webb will orbit a gravitationally stable point beyond the Sun-Earth system, so all heat sources lie in one direction and its five giant heat shields keep the telescope cold enough to liquefy air. — 00:01:27 · Earth

00:01:56 — The deployment timeline: the sighs of relief over 29 days, then calibration and first images

  • ★★★ The first sigh of relief comes about 33 minutes after launch, when the solar panels deploy and the craft powers itself; the first burn comes twelve hours after launch. — 00:01:56
  • ★★ Webb cannot be refuelled; it has all the propellant it will ever have, so the fuel used by the course correction matters for mission length. — 00:01:56
  • ★★★ Three days after launch the five-day sunshield deployment begins, to Hank the scariest step: tennis-court-sized sheets thinner than a hair, with a 600-degree Fahrenheit difference across them. — 00:02:26
  • ★★ Hank says everything in the sunshield deployment has to go right; it has been tested and it all should. (hedged) — 00:02:26
  • ★★★ Mirrors are fully deployed 13 days after launch and Webb reaches a stable orbit at L2 at 29 days; after four to five months of calibration, first images arrive five to six months after launch. — 00:02:55

00:03:24 — Curiosity near the root of being human; launch time; sign-off

  • ★★★ Hank does not know the point of being human but says curiosity is close to its root: beyond wanting a better world, we want to know and to learn. — 00:03:24 · curiosity
  • ★★ Hank says that, quite literally, we are about to see deeper than we ever have before. — 00:03:24
  • ★★ The launch is scheduled for Christmas morning at 7:20 a.m. Eastern Time. — 00:03:24 · Christmas

In the description and comments

  • ★★ The description says the launch is only the start: with a terrifyingly complex deployment, no one will breathe easy for at least two weeks after launch. — video description
  • ★★ The description thanks Dr. Amber Straughn for talking with Hank about the Webb and points to their conversation on Hankschannel. — video description · hankschannel

Threads in this video

Where the stories that moved here went next

Mentioned

Central: infrared astronomy · James Webb Space Telescope

Also: Concepts: curiosity · exoplanet · expansion of the universe · extraterrestrial life · Lagrange point

Places: Earth · Moon · Sun (star)

Events: Christmas · Christmas Eve

Only in the description or credits: Amber Straughn · hankschannel

Also centred on James Webb Space Telescope: Top 5 Awesome Things About the Webb Telescope · Can I be Space President? · It's HANKO DE MAYO!!!!! · Thoughts From the Universe - Woah

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