Earth was born dry until a cosmic collision made it a blue planet • Hacker News Board

Re: Earth was born dry until a cosmic collision made it a blue planet

#41

Post by caymanjim » Sat, Oct 04, 2025, 2:09 PM UTC

xbmcuser wrote: post #18

shireboy wrote: post #4

This could mean in the Drake equation ne -number of planets capable of life- is very small. A planet has to be hit with a comet big enough to deliver a large amount of water but not so big or fast to destroy it. And be in the Goldilocks zone of the star. Also the mass of the planet would play a part - gravity of more massive ones would be more likely to capture a comet. But again, too massive and I could see that ham…

Your assumption we need water for life to exist is in my opinion wrong. We only know Earth so assume that is what is needed for life to exist.

There's a reason life is carbon-based, and it's not random. It's the only element that works, due to abundance; ability to form many bonds; bonds that are just durable enough but not too durable. There's plenty of sci-fi about silicon-based life, but that's infeasible fantasy. And no other elements have any hope. If you have carbon-based life, you need water as solvent and medium.

It's a pretty safe assumption that all life requires water.

Re: Earth was born dry until a cosmic collision made it a blue planet

#42

Post by timbowhite » Sat, Oct 04, 2025, 2:14 PM UTC

Is this the same collision theorized to have created the moon?

Re: Earth was born dry until a cosmic collision made it a blue planet

#43

Post by warent » Sat, Oct 04, 2025, 2:18 PM UTC

xbmcuser wrote: post #18

shireboy wrote: post #4

This could mean in the Drake equation ne -number of planets capable of life- is very small. A planet has to be hit with a comet big enough to deliver a large amount of water but not so big or fast to destroy it. And be in the Goldilocks zone of the star. Also the mass of the planet would play a part - gravity of more massive ones would be more likely to capture a comet. But again, too massive and I could see that ham…

Your assumption we need water for life to exist is in my opinion wrong. We only know Earth so assume that is what is needed for life to exist.

You’re getting a lot of negative feedback for whatever reason, but you’re absolutely right.

I for one remember reading about possible silicon/methane based life, etc. Actually, here’s a whole wikipedia article on what you’re talking about.

https://en.m.wikipedia.org/wiki/Hypothetical_types_of_bioche...

Perhaps HN folks will lose your scent now and direct their snark there

Re: Earth was born dry until a cosmic collision made it a blue planet

#44

Post by mr_mitm » Sat, Oct 04, 2025, 2:27 PM UTC

crazygringo wrote: post #39

mr_mitm wrote: post #38

Earlier quoted context omitted.

The Goldilocks zone doesn't enter the Drake equation at all. As a reminder, this is the equation: https://en.wikipedia.org/wiki/Drake_equation#Equation It makes very few assumptions.

I'm assuming they were referring to this term: > n_e = the average number of planets that can potentially support life per star that has planets. The fact that the planet is neither too hot nor too cold would seem to be a major component of this term: https://en.wikipedia.org/wiki/Habitable_zone

That's just your interpretation. Take the equation at its face value and it does allow for life originating around some deep sea vents, like JamesLeonis speculated.

Re: Earth was born dry until a cosmic collision made it a blue planet

#45

Post by buran77 » Sat, Oct 04, 2025, 2:30 PM UTC

mr_mitm wrote: post #38

JamesLeonis wrote: post #35

Earlier quoted context omitted.

The Drake Equation is filled with assumptions, like life must appear on a planet in the Goldilocks zone of a star. The whole equation has only one datapoint to extrapolate from. Tweak the equation's parameters and it will predict universes that only have one civilization per galaxy or worse! We have no way of knowing what those parameters are because we haven't seen other examples. A major reason we are interested in…

The Goldilocks zone doesn't enter the Drake equation at all. As a reminder, this is the equation: https://en.wikipedia.org/wiki/Drake_equation#Equation It makes very few assumptions.

The equation itself makes no assumptions. But anyone trying to calculate something with it must.

The last five factors in the equation will be filled in by assumptions based entirely on one data point, life on Earth. From your link:

  ne = the average number of planets that can potentially support life per star that has planets.
  fl = the fraction of planets that could support life that actually develop life at some point.
  fi = the fraction of planets with life that go on to develop intelligent life (civilizations).
  fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
  L = the length of time for which such civilizations release detectable signals into space.

Can you define any one of those without assumptions, in a scientifically proven way?

Re: Earth was born dry until a cosmic collision made it a blue planet

#46

Post by acestus5 » Sat, Oct 04, 2025, 2:31 PM UTC

mr_mitm wrote: post #44

crazygringo wrote: post #39

Earlier quoted context omitted.

I'm assuming they were referring to this term: > n_e = the average number of planets that can potentially support life per star that has planets. The fact that the planet is neither too hot nor too cold would seem to be a major component of this term: https://en.wikipedia.org/wiki/Habitable_zone

That's just your interpretation. Take the equation at its face value and it does allow for life originating around some deep sea vents, like JamesLeonis speculated.

yeah you are right the Drake equation does not assume Goldilocks zone.

Re: Earth was born dry until a cosmic collision made it a blue planet

#47

Post by pavlov » Sat, Oct 04, 2025, 2:32 PM UTC

HarHarVeryFunny wrote: post #40

shireboy wrote: post #4

This could mean in the Drake equation ne -number of planets capable of life- is very small. A planet has to be hit with a comet big enough to deliver a large amount of water but not so big or fast to destroy it. And be in the Goldilocks zone of the star. Also the mass of the planet would play a part - gravity of more massive ones would be more likely to capture a comet. But again, too massive and I could see that ham…

The thing is that even for a super low probability event, the size of the universe is so huge and such events must be happening all the time. e.g. Say chance of a random planet ever being hit by a water-carrying comet is one in a billion, then with 100B - 1T planets in the milky way it'd happen here 100-1000 times. If chances are only one in a trillion, and we're the one in the milky way, then there are still another…

Do other galaxies matter here? A civilization would need to be incredibly powerful to be detectable from another galaxy.

Re: Earth was born dry until a cosmic collision made it a blue planet

#48

Post by mr_mitm » Sat, Oct 04, 2025, 2:33 PM UTC

buran77 wrote: post #45

mr_mitm wrote: post #38

Earlier quoted context omitted.

The Goldilocks zone doesn't enter the Drake equation at all. As a reminder, this is the equation: https://en.wikipedia.org/wiki/Drake_equation#Equation It makes very few assumptions.

The equation itself makes no assumptions. But anyone trying to calculate something with it must. The last five factors in the equation will be filled in by assumptions based entirely on one data point, life on Earth. From your link: ne = the average number of planets that can potentially support life per star that has planets. fl = the fraction of planets that could support life that actually develop life at some poi…

Thanks, I read that part before I shared it. It's pretty clear to me, these are pretty well defined quantities, just hard to measure. What is unclear is perhaps the definition of life. But at no point does it assume a planet must be in the Goldilocks zone. So perhaps you want to point out those assumptions you are talking about to me, because I don't see them.

Edit: the parent post has been edited substantially after I replied.

Re: Earth was born dry until a cosmic collision made it a blue planet

#49

Post by blindriver » Sat, Oct 04, 2025, 2:36 PM UTC

Absolute garbage.

The Earth has a nearly perfect circular orbit. Any collision with another planet would have pushed it off its orbit and caused it to at the very least created a more elliptical orbit that likely would have made the swings in temperature more deadly for life on Earth.

This entire article is science fiction.

Re: Earth was born dry until a cosmic collision made it a blue planet

#50

Post by alchemism » Sat, Oct 04, 2025, 2:38 PM UTC

aeonik wrote: post #33

praptak wrote: post #28

So we're not only made of elements which formed inside star(s) but also ones merged from two different planets. This is weird.

And the remnants of two neutron stars colliding.

As above, so below. Two humans colliding, too.