Search found 264 matches

by KarenRei
Fri Feb 03, 2017 2:15 am UTC
Forum: What If?
Topic: What-if 0153: "Hide the Atmosphere"
Replies: 46
Views: 12857

Re: What-if 0153: "Hide the Atmosphere"

As some side trivia, "freezing out the atmosphere" is a serious proposition for terraforming Venus. Big sunshade, freeze it out steadily, let it concentrate in the lowpoints (which deepen from the weight), manualy assist with concentrating the rest, then pave over it with insulation and co...
by KarenRei
Mon Jan 09, 2017 3:29 pm UTC
Forum: Science
Topic: Light in a fog
Replies: 14
Views: 2210

Re: Light in a fog

Bringing up a mirror just complicates it. Because sure, in the direct-collimated-sunlight case I could add a mirror beside the original solar panel that reflects light onto the back of the panel and causes its generation to double. But I could also add a mirror that would make its generation increas...
by KarenRei
Sun Jan 08, 2017 9:05 pm UTC
Forum: Science
Topic: Light in a fog
Replies: 14
Views: 2210

Re: Light in a fog

Indeed, that's what intuition says. The thing that makes me hesitate is that if you put the same double-sided solar cell in 1000W/m² direct sunlight, you only get 200W, not 400W. There's a naggling feeling that the two situations should be equivalent and I'm trying to figure out how to convince myse...
by KarenRei
Sun Jan 08, 2017 4:05 pm UTC
Forum: Science
Topic: Light in a fog
Replies: 14
Views: 2210

Re: Light in a fog

If you just had a layer of perfectly scattering fog in between the sun and the solar panel, then yes, 1/6 of the light will leave the layer in 1/6 of the solid angle available, because it's evenly distributed across all angles and we've decided that 1/6 of them are useful, while the other 5/6 of th...
by KarenRei
Sun Jan 08, 2017 1:14 pm UTC
Forum: What If?
Topic: What-If 0145: "Fire From Moonlight"
Replies: 157
Views: 37890

Re: What-If 0145: "Fire From Moonlight"

Topic related to this thread here:

viewtopic.php?f=18&t=121131&p=4129899#p4129899
by KarenRei
Sun Jan 08, 2017 12:29 am UTC
Forum: Science
Topic: Light in a fog
Replies: 14
Views: 2210

Re: Light in a fog

Probably neither. I don't think you can assume a constant 1000W/m² radiation from every direction everywhere inside the fog. Even if all the scattering inside the fog evens out, you have a huge portion of the light that'll get reflected back to the sun immediately after entering the fog. Summing up...
by KarenRei
Sat Jan 07, 2017 10:51 pm UTC
Forum: Science
Topic: Light in a fog
Replies: 14
Views: 2210

Light in a fog

I want to make sure my grasp on this is correct. Envision a fog with infinitely long extinction coefficient (perfectly reflective particles) lit up by the sun with a given solar constant (let's say 1000W/m^2). Inside the fog you place a 20% efficient 1m^2 solar panel that functions equally well from...
by KarenRei
Wed Dec 07, 2016 12:09 pm UTC
Forum: What If?
Topic: What-If 0153: "Peptides" [removed]
Replies: 22
Views: 9839

Re: What-If 0153: "Peptides"

With rare but extant Selenocysteine (O) and Pyrrolysine (U) and without the colonial spelling, "Deinsitutionali s ation" is a perfectly cromulant peptide chain... Well, geez, if you're going to do that then you can do "pneumonoultramicroscopicsilicovolcanoconiosis" (45 letters) ...
by KarenRei
Tue Dec 06, 2016 12:59 pm UTC
Forum: What If?
Topic: What-If 0153: "Peptides" [removed]
Replies: 22
Views: 9839

Re: What-If 0153: "Peptides"

This question is really weak. Is knowledge of grep and the mere existence of "/usr/share/words" really that rare of a skillset? egrep -i "^[ARNDCEQGHILKMFPSTWYV]*$" /usr/share/dict/words | awk '{print length, $0}' | sort -n | cut -d " " -f2- egrep -i "^(ALA|ARG|ASN...
by KarenRei
Sun Oct 30, 2016 8:58 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1749: "Mushrooms"
Replies: 47
Views: 7362

Re: 1749: "Mushrooms"

I've got mushrooms in the garden. I've got Armillaria mellea . It ate the hedge. It looks a lot like Galerina marginata so I'm not going to eat it right back. Mushrooms are the primary reason I wish that smartphones came with DNA sequencers. :Þ Re. A. virosa/Destroying Angel... it's famous for its ...
by KarenRei
Fri Oct 21, 2016 4:13 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1749: "Mushrooms"
Replies: 47
Views: 7362

Re: 1749: "Mushrooms"

A friend of mine calls fungi "the vampires of the plant world".

Not exactly phylogenically correct, but...
by KarenRei
Wed Oct 19, 2016 3:23 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1747: "Spider Paleontology"
Replies: 43
Views: 7037

Re: 1747: "Spider Paleontology"

I have to admit that I'd be totally chuffed to find evidence that Dinosaurs* built elaborate bowers surrounded by carefully segregated piles of colored materials, like the bowerbird . Unfortunately, that's probably about as unlikely as Randall's future folk learning about spiderwebs without using t...
by KarenRei
Tue Oct 18, 2016 4:10 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1747: "Spider Paleontology"
Replies: 43
Views: 7037

Re: 1747: "Spider Paleontology"

So, if I'm understanding you correctly, you're arguing that the majority of the diversity among dinosaurs can be found in birds, a lineage 65 million years old, even though dinosaurs had already been diversifying for 170 million years? To not put too fine of a point on it: the dinosaurs are defined ...
by KarenRei
Tue Oct 18, 2016 2:11 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1747: "Spider Paleontology"
Replies: 43
Views: 7037

Re: 1747: "Spider Paleontology"

Birds have had 65 million years to diversify. And dinosaurs had 170 million years to diversify before getting up to the point of further diversifying into the subset of dinosaurs known as birds - your point? As birds are a subset of dinosaurs, it's inherent that their diversity will be less than th...
by KarenRei
Mon Oct 17, 2016 11:10 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1747: "Spider Paleontology"
Replies: 43
Views: 7037

Re: 1747: "Spider Paleontology"

Probably best done with atomic-level physical crystal manipulation (multi-atom level of resolution, to deal with error correction after random radiation hits.... Store it at L4 or L5 (or both?) of Mercury (stable, relatively clean of crossing asteroids compared to other planets), with a planar whip...
by KarenRei
Mon Oct 17, 2016 1:38 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1747: "Spider Paleontology"
Replies: 43
Views: 7037

1747: "Spider Paleontology"

http://imgs.xkcd.com/comics/spider_paleontology.png Alt-text: "Whenever you see a video of birds doing something weird, remember: Birds are a small subset of dinosaurs, so the weirdness of birds is a small subset of the weirdness of dinosaurs." --- I think people who design CG dinosaurs w...
by KarenRei
Tue Sep 13, 2016 11:36 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1732: "Earth Temperature Timeline"
Replies: 523
Views: 66924

Re: 1732: "Earth Temperature Timeline"

SecondTalon wrote:
Stargazer71 wrote:meaniehead as a pejorative about a dozen times


Here's what's going to happen.... ... (snip)


Where's a "Like" button when you need one?
by KarenRei
Tue Sep 13, 2016 9:56 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1732: "Earth Temperature Timeline"
Replies: 523
Views: 66924

Re: 1732: "Earth Temperature Timeline"

So, apparently Elon Musk is an XKCD fan ;)

https://twitter.com/elonmusk/status/775632728548970500
by KarenRei
Mon Aug 22, 2016 2:21 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1723: "Meteorite Identification"
Replies: 30
Views: 7746

Re: 1723: "Meteorite Identification"

Despite knowing that the vast majority of things people suspect are meteorrites aren't, I once got tricked into thinking that an unusual shaped ("fingerprint"-looking), highly naturally polished piece of basalt might be when it easily deflected my studfinder. It was then that I learned tha...
by KarenRei
Sat Jul 09, 2016 12:50 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1702: "Home Itch Remedies"
Replies: 33
Views: 5328

Re: 1702: "Home Itch Remedies"

Hehe ;) As a side note, the Icelandic language is unusually easy for making duck jokes because the word for "duck" and all of its various declensions (önd, andar, endur, andir, anda, öndum...) closely resembles a number of differents words used in forming compounds.(words equivalent to the...
by KarenRei
Mon Jul 04, 2016 8:21 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1702: "Home Itch Remedies"
Replies: 33
Views: 5328

Re: Home Itch Remedies

So the best home remedy is to move to Iceland Not a good idea... The name of the lake (Icelandic mý ("midge") and vatn ("lake"); the lake of midges) comes from the huge numbers of midges to be found there in the summer. Except that they don't bite. They form big clouds, and look...
by KarenRei
Tue May 10, 2016 9:36 am UTC
Forum: Mathematics
Topic: Seemingly simple
Replies: 16
Views: 3034

Re: Seemingly simple

C/x = B/sqrt(B^2 -(A-x)^2) This should be C/x = B/sqrt(B^2 + (A-x)^2), since sqrt(B^2 + (A-x)^2) is the length of the hypotenuse of the large right triangle. Then, C sqrt(B^2 + (A-x)^2) = B x C^2 (B^2 + (A-x)^2) = B^2 x^2 B^2 C^2 + A^2 C^2 - 2 A C^2 x + C^2 x^2 = B^2 x^2 0 = (B^2 - C^2) x^2 + (2 A ...
by KarenRei
Tue May 10, 2016 7:49 am UTC
Forum: Mathematics
Topic: Seemingly simple
Replies: 16
Views: 3034

Re: Seemingly simple

C/x = B/sqrt(B^2 -(A-x)^2) C = x * B/sqrt(B^2 -(A-x)^2) x * B/sqrt(B^2 -(A-x)^2) - C = 0 This isn't in the form Ax^2 + Bx + C = 0... and I don't remember how to get it in that form ;) And Wolfram Alpha last night was just looping forever, while today it says "Standard computing time exceeded&qu...
by KarenRei
Tue May 10, 2016 12:49 am UTC
Forum: Mathematics
Topic: Seemingly simple
Replies: 16
Views: 3034

Seemingly simple

Either I'm tired, an idiot, or this problem isn't as easy as it looks (solve for X; all corners that look like right angles are right angles):

Image

Can anyone enlighten me as to which one it is?
by KarenRei
Thu Mar 17, 2016 2:51 am UTC
Forum: What If?
Topic: What-If 0148: "Eat the Sun"
Replies: 40
Views: 15747

Re: What-If 0148: "Eat the Sun"

Meh, Cadbury Creme Eggs are nothing. Here in Iceland we have "Páskaegg" (lit. "Easter Egg"), which are like this: Not purely a purely mid-Atlantic(-ridge) phenomenon, I assure you. I can't definitively speak for the US (I presume that it happens!) but the shops in the UK are ful...
by KarenRei
Wed Mar 16, 2016 7:06 pm UTC
Forum: What If?
Topic: What-If 0148: "Eat the Sun"
Replies: 40
Views: 15747

Re: What-If 0148: "Eat the Sun"

Now I just want to contribute to Randall's Creme Egg pile... Meh, Cadbury Creme Eggs are nothing. Here in Iceland we have "Páskaegg" (lit. "Easter Egg"), which are like this: https://c1.staticflickr.com/8/7615/17001375115_6e346a56d4.jpg http://www.visir.is/apps/pbcsi.dll/storyim...
by KarenRei
Sat Feb 20, 2016 9:33 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1645: "Toasts"
Replies: 81
Views: 13904

Re: 1645: "Toasts"

Image
by KarenRei
Fri Feb 19, 2016 5:42 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1645: "Toasts"
Replies: 81
Views: 13904

Re: 1645: "Toasts"

Okay, I guess my mind is in the gutter...

Fatheads for my real friends and real head for my fat friends.
Hotrods for my real friends and real rods for my hot friends.
Manholes for my real friends and a real holes for my man-friends.

... this is getting out of hand...
by KarenRei
Sat Feb 13, 2016 5:39 pm UTC
Forum: Science
Topic: Venus chemical engineering
Replies: 0
Views: 3063

Venus chemical engineering

Hi all. I've been idly thinking a lot about how to provision a floating colony on Venus in a simple, reliable manner. There are two issues I'm having a bit of trouble on: 1) Removal (to an exhaust stream) of SO2 from a stream also containing H2O and O2 2) Either: 2a) Separation of individual acids f...
by KarenRei
Wed Feb 10, 2016 11:00 pm UTC
Forum: What If?
Topic: What-If 0145: "Fire From Moonlight"
Replies: 157
Views: 37890

Re: What-If 0145: "Fire From Moonlight"

Simplest case: take a spherical black body at thermal equilibrium. Then put it next to a mirror. Not even a focusing mirror, just a simple plane. Doesn't the side of the black body facing the mirror end up warmer than the side facing away? This does assume the background is cooler than the black bo...
by KarenRei
Wed Feb 10, 2016 10:31 pm UTC
Forum: Science
Topic: Landing rockets upright is unnecessary?
Replies: 61
Views: 9664

Re: Landing rockets upright is unnecessary?

This would require an infinitely large nozzle, so one does as much as they can with the nozzle that they have. The more gas involved (even gas that doesn't take part in the reaction), the more fully they can approach ambient for a given-sized nozzle. No, and actually the space shuttle main engines ...
by KarenRei
Wed Feb 10, 2016 4:46 pm UTC
Forum: Science
Topic: Is the entire universe a black hole?
Replies: 13
Views: 3076

Re: Is the entire universe a black hole?

Some interesting reading on the subject: http://cds.cern.ch/record/348993/files/9803052.pdf They posit an inflation-driven effect at high densities (a dilation gravity) that would mean that there's no such thing as a singularity, and that both black holes and our universe would be versions of the sa...
by KarenRei
Wed Feb 10, 2016 2:30 pm UTC
Forum: Science
Topic: Landing rockets upright is unnecessary?
Replies: 61
Views: 9664

Re: Landing rockets upright is unnecessary?

Nope. Beyond a certain expansion ratio the vapour freezes solid. You can't expand solid material any further. Now you're back to the earlier, primary point: the advantages of having a working fluid (that's one of many). Nor is an infinite length nozzle optimal, because the nozzle weighs something. ...
by KarenRei
Tue Feb 09, 2016 9:01 pm UTC
Forum: Science
Topic: Landing rockets upright is unnecessary?
Replies: 61
Views: 9664

Re: Landing rockets upright is unnecessary?

A rocket's efficiency is at a maximum when all of the heat of combustion and all of the pressure have been fully expanded to ambient temperature and pressure. No. That's a finite length nozzle, except in a perfect vacuum. And even there, there's a optimum nozzle length where increasing the length a...
by KarenRei
Tue Feb 09, 2016 4:40 pm UTC
Forum: Science
Topic: Landing rockets upright is unnecessary?
Replies: 61
Views: 9664

Re: Landing rockets upright is unnecessary?

I think what some people are suggesting is essentially a scramjet/ramjet where the flame-holder is a rocket engine that provides the initial startup thrust to get it up to ramjet operational speeds then throttles back as the ramjet portion starts providing more thrust. Not exactly. The concept pres...
by KarenRei
Tue Feb 09, 2016 4:21 pm UTC
Forum: Science
Topic: Wendelstein 7-X
Replies: 43
Views: 6967

Re: Wendelstein 7-X

So, you have a variety of things carrying energy out of the reactor. Examples include: * The divertor (think "exhaust pipe") juts into the outer edges of plasma stream where it gets heavily bombarded by alpha particles (read: the helium it's trying to remove) * The first wall is subject to...
by KarenRei
Thu Feb 04, 2016 2:05 pm UTC
Forum: Science
Topic: Wendelstein 7-X
Replies: 43
Views: 6967

Re: Wendelstein 7-X

The magnets repel the plasma away from the vessel walls. Increasing the strength of the field increases the force of this repulsion, thus squeezing the plasma into a smaller space. I'm a little bit skeptical. What magnets repel the plasma away from the vessel wall? Magnets don't "repel plasma&...
by KarenRei
Mon Feb 01, 2016 11:10 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1637: "Salt Mine"
Replies: 57
Views: 10247

Re: 1637: "Salt Mine"

mdog wrote:Hey, maybe protons only decay when they want to.


The electrons.... they're ANGRY!
by KarenRei
Mon Feb 01, 2016 1:17 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1633: "Possible Undiscovered Planets"
Replies: 104
Views: 14779

Re: 1633: "Possible Undiscovered Planets"

How is continuing to snub Ceres a compromise? Ceres is the best! It's a cool little perfect (dwarf) planet, just barely big enough to be round on its own. Meh, Ceres isn't "just big enough to be round on its own". Vesta is a better description of that boundary, sort of a half-equilibrium ...
by KarenRei
Sun Jan 31, 2016 2:19 am UTC
Forum: What If?
Topic: What-If 0143: "Europa Water Siphon"
Replies: 52
Views: 14671

Re: What-If 0143: "Europa Water Siphon"

I think the siphon in a vacuum question hinges on what the liquid does when the pressure drops to zero. Let's say there is an intermolecular force f between molecules in the liquid. Randall mentioned this in comment 5, and I and others have commented extensively on this above. It's as if the water ...

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