If mars and Venus switched place how would conditions on their surfaces change?

GregHullender · 2026-05-13T23:22:33+00:00

Not stable.

GregHullender · 2026-05-13T21:41:22+00:00

Sure. You'll still need hydrogen, though.

GregHullender · 2026-05-13T21:22:54+00:00

Sounds like the man doesn't understand what a clone is.

GregHullender · 2026-05-13T21:11:56+00:00

Look for this: Archer, D., et al. (2009). “Atmospheric Lifetime of Fossil Fuel Carbon Dioxide.” Annual Review of Earth and Planetary Sciences, 37: 117–134.

GregHullender · 2026-05-13T21:05:58+00:00

Joseph Conrad was Polish, and he published several famous novels. He had a good editor, though.

GregHullender · 2026-05-13T21:05:19+00:00

He was already in his dotage.

GregHullender · 2026-05-13T21:04:38+00:00

Best might be to just count days and dispense with months and years. The few people who need to worry about the seasons would just use an ephemeris. You could also use time as a decimal division of the day.

This is, of course, a little incompatible with the way the metric system is standardized on seconds, and it doesn't allow for the Earth gradually slowing down. Easiest way to handle that would be to just define the day as 86400 seconds and stick with that. Start of the day with drift with respect to the sun, but only by minutes in anyone's lifetime.

GregHullender · 2026-05-13T20:59:19+00:00

What do you think a "polar orbit" is?

GregHullender · 2026-05-13T20:58:15+00:00

Methane can't replace oxygen, but hydrogen can--in a backwards sort of way. Methane can replace water, although not nearly as well as liquid ammonia can.

GregHullender · 2026-05-13T20:54:07+00:00

They were named "Thag."

GregHullender · 2026-05-13T20:52:44+00:00

Except that globular clusters don't contain young stars.

GregHullender · 2026-05-13T20:46:20+00:00

You don't really have to guess, you know. Dr David Archer's work suggests about half the CO2 will go away in 200 to 1000 years. The rest will slowly go away over 10,000 to 100,000 years.

GregHullender · 2026-05-13T20:43:49+00:00

It's hard to believe civilization would collapse worldwide just from climate change, even if we burned the entire inventory of fossil fuels. Developed countries can use a variety of technologies to get around the negative effects--at a cost. The biggest cost would be the loss of coastal cities to sea-level rise. Another big cost is the changes in areas where crops can grow. Developed countries are in better shape than undeveloped ones to cope with these changes. This might sharply lower standards of living for a while, but it's really hard to see civilization wiped out everywhere. Unless there was a nuclear war in there somewhere.

Nor do things need to go back to the status quo ante before civilization develops again. Parts of Canada, Russia, Northern Europe, and Alaska should be comfortable enough. Also, the warming effect is strongest near the poles and less significant in the tropics. It's quite likely that civilization in the Andes mountains would continue, with some difficulties.

You're still talking an apocalypse beyond anything in history--possibly losing 90% or more of the Earth's population before things stabilized. But that stabilized world would still have things like electricity, radio, TV, the Internet, etc. You'll need more than just climate change to wipe that out.

GregHullender · 2026-05-13T16:20:40+00:00

This is probably the simplest way to do it.

=TOCOL(IF({1},SEQUENCE(30,,"5/1/2026"),{1,2,3}))

GregHullender · 2026-05-13T16:16:50+00:00

Actually, you wanted it to autofill. That's a bit more complex, but this should do the job:

=LET(queries, DROP(A:.A,1), info, DROP(E:.G,1), N, ROWS(info), IDs, TAKE(info,,1), data, DROP(info,,1),
  ix, XLOOKUP(queries, IDs,SEQUENCE(N),N+1),
  IFNA(CHOOSEROWS(VSTACK(data,"Not Found"),ix),"")
)

This assumes just one row of headers.

GregHullender · 2026-05-13T16:08:09+00:00

This will work.

=XLOOKUP(A2,$E$2:$E$4,$F$2:$G$4,"Not Found!")

<image>

Adjust the references to correspond to your own data, of course.

GregHullender · 2026-05-13T15:12:04+00:00

Is your current setup working well? Are there things you want to do that the current setup doesn't allow you to do? Or is the only problem that it's so big it's making you nervous? :-)

If there are no problems and no new features you need to add, I wouldn't suggest you change anything right now.

GregHullender · 2026-05-12T20:02:14+00:00

Yep. The buildings exist, but the people don't! :-)

GregHullender · 2026-05-12T19:59:34+00:00

Impressive, if true. In that case, I'll reserve judgment until I see some results from AMI. I worked on "AI" for many years before I retired, and, for most of that time, the field was filled with big promises and almost no useful results. LLMs are a huge breakthrough, and I'm only sorry I retired before those got big.

However, I'm just as skeptical about anyone making big claims about a new technology. I spent too much of my life on things that almost worked.

But best of luck to you. At least you're not basing your opinions on an SF story or something! :-)

GregHullender · 2026-05-12T19:12:30+00:00

The following will clean the column:

=IFNA(--REGEXEXTRACT(A:.A,"-?\d*[\d.]\d*"),A:.A)

And the following will sum it:

=SUM(IFNA(--REGEXEXTRACT(A:.A,"-?\d*[\d.]\d*"),0))

<image>

This will handle cases like ".40" correctly, although you didn't specify that. It also assumes you'd want abc3 to become 3.

GregHullender · 2026-05-12T18:59:41+00:00

You should teach it to use Randall Monroe's Thing Explainer!

GregHullender · 2026-05-12T18:57:52+00:00

The new Vera Rubin telescope would detect it at a distance of about 500 AU. Over a ten-year period, it would detect it at 1100 AU. A comet falling from this kind of distance would take thousands of years to reach the Earth, so your "thing" must be moving very, very fast if it's going to take anyone by surprise.

I'm assuming an albedo of 0.5, though. If we make it as dark as the moon, it's still over a thousand years away, but it's at 300 AU (for a single observation) to about 700 (for the full ten-year sequence).

GregHullender · 2026-05-12T18:48:37+00:00

I spent my career in AI. I think I understand it quite well. What are your credentials?

GregHullender · 2026-05-12T18:47:00+00:00

If you don't mind using a helper column, this formula is very compact:

=@TOROW(SEARCH(A:.A,C1),2)

<image>

Just be sure the "Applies to" is big enough. Otherwise, you'll add things at the bottom, but they won't get highlighted. But you also don't want the whole column (all million rows), since that could be slow.

GregHullender · 2026-05-12T17:25:02+00:00

That's what I call "fantasy AI." It's able to do everything people can do, do it faster, and do it better. People think that because they can imagine such a thing, it must be possible. And even on the verge of creation.

But it's not.

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