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They Say it Gets Colder

2020-09-18 · explainer · Hank · 3:55 · watch on YouTube

Topic: Science & nature · mode: News analysis · tags: timely hook, self promotion, community lore

Prompted by this week's report of unexplained phosphine in Venus's atmosphere, Hank explains why Venus's temperate cloud layer is a candidate for microbial life and why the claim needs a mission to confirm, then argues that life elsewhere in the universe is not an extraordinary claim, since what happened once can probably happen again a lot.

What is said

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

00:00:00 — The habitable zone is about where we could live; Enceladus and Europa; Mars and Venus once habitable

  • ★★ Hank says the search for Earth-like planets in a star's habitable zone is more about whether we could live there than whether there could be life there. — 00:00:00 · Earth
  • ★★ Hank says the places outside Earth most conducive to life lie outside the habitable zone. — 00:00:00 · Earth
  • ★★ Hank says Enceladus and Europa, icy moons of gas giants, definitely have giant oceans of liquid water beneath their icy surfaces. — 00:00:29
  • ★★ Hank says Mars and Venus were probably habitable for a long time; Mars is in the habitable zone, Venus is not. (hedged) — 00:00:29 · Mars

00:00:58 — Venus: a hellish surface but a Florida-like, acidic cloud layer where microbes might live

  • ★★ Hank says highs on Venus are about 900 degrees Celsius, hot enough to melt lead. — 00:00:58
    • a number in question (doubtful): "900 degrees Celsius" — check against the recording
  • ★★ Hank says the search for life in the solar system focused on Mars not because it is the best candidate but because it is much easier to work with. — 00:00:58 · Mars
  • ★★ Hank says unexplained observations of Venus, such as cloud areas that darken, have led people to look at how life might exist there. — 00:00:58
  • ★★★ Hank says higher up it gets cold enough for steam to condense into water droplets: 40 to 60 kilometres above Venus's surface, temperatures and pressures are like Florida. (playful) — 00:00:58 · Florida
  • ★★ Hank says the droplets are highly concentrated sulfuric acid, and no life on Earth could live in water anything like that acidic. — 00:01:39 · Earth
  • ★★ Hank describes the hypothesis: microbes might live in the droplets, go dormant as spores when falling droplets evaporate, and be tossed back up into the nicer atmosphere. (speculative) — 00:01:39

00:02:08 — This week's phosphine finding, possible explanations, and the need for extraordinary evidence

  • ★★★ Hank says it was a big deal this week (week of 14 September 2020) when scientists announced a seemingly impossibly high concentration of phosphine in Venus's atmosphere. — 00:02:08
  • ★★ Hank says phosphine is nasty for humans but some microorganisms, bacteria that don't use oxygen, produce it as a waste product. — 00:02:08
  • ★★ Hank says phosphine cannot last long in Venus's atmosphere, since processes would break it down almost immediately, so something must be creating it. — 00:02:08
  • ★★ Hank says an unknown geochemical process could produce the phosphine, and figuring that out would itself be a big deal. (hedged) — 00:02:38
  • ★★ Citing 'extraordinary claims require extraordinary evidence', Hank says proof of life would need a visit to Venus's upper atmosphere, as the paper's authors confirm. — 00:02:38
  • ★★ Hank imagines a mission to Venus's upper atmosphere will happen in his lifetime, which he finds super exciting. (hedged) — 00:02:38

00:03:05 — Life elsewhere is not an extraordinary claim; sign-off

  • ★★★ Hank says he doesn't think it is an extraordinary claim that there is life elsewhere in the universe. — 00:03:05
  • ★★★ Hank argues that although we have never duplicated the chemistry of life's origin in a lab, it definitely happened, and what happens once can happen again, probably a lot. — 00:03:05
  • ★★ Hank says life on a neighbouring planet would be extremely exciting but maybe not as surprising as one might think. (hedged) — 00:03:05

00:03:34 — Plug for SciShow Space

  • ★★ Hank recommends SciShow Space, which covers this kind of topic twice a week on YouTube, hosted by him, Caitlin and Reid. — 00:03:34 · SciShow Space, YouTube

In the description and comments

  • ★★ The description says alien life with clear signs of relation to Earth life would show that life can and does travel between planets. — video description · Earth
  • ★★ The description says alien life clearly unrelated to Earth life would show that life arises relatively easily and that the universe is filled with living systems. — video description · Earth
  • ★★ The description adds that life may be rare and may have arisen only once in our solar system; the only way to find out is to keep looking. — video description
  • ★★ The description says that if life is found on another planet, we will be able to figure out pretty quickly whether it is related to life on Earth. — video description · Earth

Threads in this video

Where the stories that moved here went next

Mentioned

Central: extraterrestrial life · phosphine · Venus

Also: Projects: SciShow Space

Works: Phosphine gas in the cloud decks of Venus

Organizations: YouTube

Concepts: abiogenesis · anaerobic organism · circumstellar habitable zone · Sagan standard · sulfuric acid

Places: Earth · Enceladus · Europa · Florida · Mars · Milky Way · Solar System

Only in the description or credits: Caitlin Hofmeister · Reid Reimers

Also centred on extraterrestrial life: Where are the Space Aliens?! · We just had our first interstellar visitor...and it's weird. · Aliens · Is it Good or Bad that we Haven't Met Aliens? · Fine, I'll Talk About the Drones… · This Might Actually be Happening

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