/sci/ - Science & Math » Thread #5209640

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Anonymous Wed 31 Oct 2012 05:35:51 No.5209640 View View Reply Original Report

At what distance from earth would you have to drop a steak for it to be cooked medium rare by reentry into the atmosphere?

Anonymous

Anonymous Wed 31 Oct 2012 23:54:11 No.5211676 Report

Quoted By:

>>5211669
But if it's too hot it just burns. It has to reach the right maximum temperature, in which case it would be cold after the entire flight. The only way to get it warm on your plate is to catch it mid air.

Sugar !HVRS00ciDo

Sugar !HVRS00ciDo Wed 31 Oct 2012 23:56:25 No.5211680 Report

Quoted By: >>5212642 >>5212712

The real question is, how would you slow it down enough so that when it reached the surface of Earth it wouldn't disintegrate on impact

Anonymous

Anonymous Wed 31 Oct 2012 23:59:02 No.5211688 Report

Quoted By: >>5211692 >>5211716 >>5211718

Wow /sci/ really is retarded

Some people are massively overcomplicating it to look clever, and others are just plain missing the point.

The heat from re-entry doesn't come from Gravitational Potential Energy, it comes from Kinetic energy. Felix didn't burst into flames but if we hurled him down from that height at the speed of a meteorite he would.

Take the terminal velocity as negligible compared to the speed you'd need to chuck it out of the spaceship at and do a back of the envelope calculation assuming all the KE is converted to heat to get a rough ballpark figure.

Anonymous

Anonymous Thu 01 Nov 2012 00:01:58 No.5211692 Report

Quoted By: >>5211711

>>5211688
Then why do space shuttles get so hot on re entry? They certainly don't have the speed of meteorites.

Anonymous

View Same Google ImgOps iqdb SauceNAO death-of-jack.jpg, 39KiB, 400x322

Anonymous Thu 01 Nov 2012 00:07:11 No.5211703 Report

Quoted By:

>>5211649
when was the last time you were tested?

Anonymous

Anonymous Thu 01 Nov 2012 00:09:54 No.5211711 Report

Quoted By: >>5211722

>>5211692
red bull guy's top speed was 0.37 km/s
deorbiting space craft have speed of 8 km/s
return from the moon is 11 km/s
meteorites are in 15-70 km/s range
apparently many km/s is enough to burn you, unless you have an ablative shield.

Anonymous

Anonymous Thu 01 Nov 2012 00:12:32 No.5211716 Report

Quoted By: >>5211739

>>5211688
You can't just say KE=Q, if you are using energy equations, you need some type of boundary. If the boundary is your entire steak, there is going to be work done on the system from the drag force, Heat transfer to the steak from conduction(could be convection? Not quite sure actually) from the surrounding air that is heated up from friction. Certainly the internal energy of the steak is increasing, otherwise the temperature of the steak wouldn't increase. Gravitational Potentinal Energy could be neglected, but it is needed to answer OP's original question, the distance needed to drop the steak.

Anonymous

Anonymous Thu 01 Nov 2012 00:12:56 No.5211718 Report

Quoted By:

>>5211688
>assuming all the KE is converted to heat
assuming half of the KE is converted to heating the steak, the other half to heating the air

Anonymous

Anonymous Thu 01 Nov 2012 00:14:24 No.5211722 Report

Quoted By: >>5211748

>>5211711
So basically for the first bit of the fall you'd have to attach the steak to a rocket to bring it up to speed.

Anonymous

Anonymous Thu 01 Nov 2012 00:20:16 No.5211739 Report

Quoted By: >>5211759 >>5211802

>>5211716
>You can't just say KE=Q

Sure we can this is just an order of magnitude thing for fun.

If you're looking for an exact answer that's hardly the biggest source of error. The steak would probably immediately break up for a start.`

Sugar !HVRS00ciDo

Sugar !HVRS00ciDo Thu 01 Nov 2012 00:23:13 No.5211748 Report

Quoted By:

>>5211722
not necessarily, attach it to an orbiting object, like a space station, and drop it.

Anonymous

Anonymous Thu 01 Nov 2012 00:25:55 No.5211756 Report

Quoted By:

>>5209698
>Medium well
Fuck yeah

Anonymous

Anonymous Thu 01 Nov 2012 00:27:30 No.5211759 Report

Quoted By: >>5211774

>>5211739
No you can't. That was already tried here >>5209751
and the answer was 7.8km which is obviously way too low.

Anonymous

Anonymous Thu 01 Nov 2012 00:36:14 No.5211774 Report

Quoted By: >>5211829

>>5211759
I'm not talking about Gravitational Potential Energy. Obviously that's wrong.

I'm talking about getting it up to speed before it hits the atmosphere by throwing it which is the only real way you could do this.

Just put in some numbers and it would need to be in the order of 1000's of metres per second (so some 1-10 km/s let's say).

I assumed it would heat up by 200 degrees and remain at that temperature for freefall at terminal velocity for however long it takes steaks to cook.

E = mcT = 1/2mv^2

v = sqrt(2cT) = sqrt(6.4e5) is gonna be somewhere in the range of hundreds to thousands of metres per second. The real value will obviously be higher for various reasons. I used c = 1.6 kJ/kgK from earlier in the thread.

Anonymous

View Same Google ImgOps iqdb SauceNAO At least you tried.jpg, 175KiB, 589x564

Anonymous Thu 01 Nov 2012 00:42:56 No.5211785 Report

Quoted By: >>5211839

>>5209751
>Of course this is assumes all of the energy went into the steak, so the actual figure would be a bit higher.
>the actual figure would be a bit higher
>a bit higher
>a bit
Look at this faggot.

Allow me to throw out a few of the many concepts that would relate to this problem:
>Forced convection
>Variation in atmospheric density and temperature with altitude
>Stagnation conditions
>Thermal conductivity of the meat itself (MIGHT be negligible, but probably won't be)
>Actual average drag coefficient of the meat (remember, it will change depending on the meat's orientation), including wave drag (which will also vary once you go transonic)
Even that will only get you a first approximation.

Anonymous

Anonymous Thu 01 Nov 2012 00:44:23 No.5211789 Report

Quoted By:

>>5209871
Cool, it's damn near piecewise.

Anonymous

Anonymous Thu 01 Nov 2012 00:49:12 No.5211802 Report

Quoted By: >>5211805

>>5211739
That won't even get you into the right order of magnitude. Most of the heat will be carried away by the air itself.

Hell, for MOST purposes in aerodynamics, flow is regarded as fully isotropic.

Anonymous

Anonymous Thu 01 Nov 2012 00:50:11 No.5211805 Report

Quoted By:

>>5211802
Err, isentropic. And by that I actually mean adiabatic.

Fuck.

Anonymous

Anonymous Thu 01 Nov 2012 01:04:21 No.5211829 Report

Quoted By:

>>5211774
How about setting the steak at a distance from the earth where it could enter an extremely weak orbit and, after gaining a significant amount of speed, reenter earth's atmosphere and cook? If that were possible, which it likely isn't, then the steak would not have to be shot at the earth.

Anonymous

Anonymous Thu 01 Nov 2012 01:07:49 No.5211839 Report

Quoted By:

>>5211785

This isn't computational fluid dynamics it's a back of the envelope calculation.

Also I don't see how things like the drag coefficient and varying atmospheric density are really relevant. I'm not trying to model it's descent, just considering the beginning and end conditions.

Anonymous

Anonymous Thu 01 Nov 2012 02:28:37 No.5212100 Report

Quoted By: >>5212189

Could someone use this as a thesis or project? I'd love to see a paper on this.

Anonymous

Anonymous Thu 01 Nov 2012 02:35:15 No.5212123 Report

Quoted By:

>>5211311
If I were to guess, probably the latter - reentry would only last for a matter of minutes, not nearly enough time to consider the effects of small changes in momentum due to Yarkovsky

Anonymous

Anonymous Thu 01 Nov 2012 02:51:00 No.5212189 Report

Quoted By: >>5212221 >>5212251

>>5212100
or something like xkcd what-if comic.

Anonymous

Anonymous Thu 01 Nov 2012 02:57:57 No.5212221 Report

Quoted By: >>5212249

>>5212189
Send it in! I'd love to see something on xkcd that came from a /sci/ thread

Anonymous

View Same Google ImgOps iqdb SauceNAO Bill Clinton laughs at you.jpg, 18KiB, 240x300

Anonymous Thu 01 Nov 2012 03:02:46 No.5212236 Report

Quoted By: >>5212280

Thank you based /sci/, this has been one of the most entertaining threads I've read in a while.

Anonymous

Anonymous Thu 01 Nov 2012 03:05:11 No.5212249 Report

Quoted By: >>5212608

>>5212221
Done.

Anonymous

Anonymous Thu 01 Nov 2012 03:05:21 No.5212251 Report

Quoted By:

>>5212189
Was actually my original thought, but I was AFK at the time and forgot about it.

Anonymous

Anonymous Thu 01 Nov 2012 03:13:47 No.5212280 Report

Quoted By: >>5212405

>>5212236
>dat filename

how do we archive this thread

Anonymous

Anonymous Thu 01 Nov 2012 03:56:42 No.5212405 Report

Quoted By:

>>5212280
Here

http://chanarchive.org/4chan/sci

Anonymous

Anonymous Thu 01 Nov 2012 04:10:13 No.5212462 Report

Quoted By:

>>5210794
8 minutes. If it cooks in 5 its gonna be burnt pizza.

Anonymous

Anonymous Thu 01 Nov 2012 05:01:39 No.5212608 Report

Quoted By: >>5212617

>>5212249
... or well done?

Personally, I'm an experimentalist. I want to strap steaks to all surfaces of the SpaceX Dragon capsule and see which ones survive, much less cook properly.

Anonymous

Anonymous Thu 01 Nov 2012 05:05:08 No.5212617 Report

Quoted By:

>>5212608
Steak Heat Shield - Protect your craft and enjoy a delicious steak dinner after landing.

*Baked potato landing struts not included

Anonymous

Anonymous Thu 01 Nov 2012 05:14:26 No.5212642 Report

Quoted By: >>5212885

>>5211680
yeah, how might we go about slowing down an object descending rapidly through earth's atmosphere. if only some sort of simple device capable of increasing drag had been invented, it would be able to save our steak, and may have even saved that poor red bull man from slamming into a mountain at the speed of sound.

Anonymous

Anonymous Thu 01 Nov 2012 05:15:58 No.5212645 Report

Quoted By: >>5212744

>>5211649
>eating raw beef

Enjoy your prions.

Anonymous

Anonymous Thu 01 Nov 2012 05:36:14 No.5212712 Report

Quoted By: >>5212738 >>5212798

>>5211680
Well, depending on its angle of descent it will probably aerobrake part of the way down. Then we can bring it the rest of the way using chutes, thrusters, or a combination of both.

Maybe have one of those big airbag things blow up around it as it nears the ground.

Anonymous

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Anonymous Thu 01 Nov 2012 05:43:15 No.5212738 Report

Quoted By: >>5212757

>>5212712
Steak skycrane!!

Once the steak reaches the lower atmosphere and hits terminal velocity, a 'harness' of sorts rendezvous with and captures the steak before engaging the thrusters.

The thrusters slow the steak to descent speed and maneuver it to the landing site.

20 meters above the ground, the skycrane lowers the steak ever so gently onto a waiting plate which already contains a baked potato, corn, and a dinner roll.

Bon apetit

Anonymous

Anonymous Thu 01 Nov 2012 05:45:21 No.5212744 Report

Quoted By: >>5212751

>>5212645
Cooking doesn't reliably destroy prions.

Anonymous

Anonymous Thu 01 Nov 2012 05:49:27 No.5212751 Report

Quoted By:

>>5212744

Doesn't ever destroy prions, to be more accurate. Prions have a resistance to thermal denaturation much higher than anything else in your meat.

Anonymous

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Anonymous Thu 01 Nov 2012 05:51:12 No.5212757 Report

Quoted By:

>>5212738
>20 meters above the ground, the skycrane lowers the steak ever so gently onto a waiting plate which already contains a baked potato, corn, and a dinner roll.
MAKE IT HAPPEN /sci/!!!

Anonymous

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Anonymous Thu 01 Nov 2012 05:51:47 No.5212758 Report

Quoted By:

Anonymous

Anonymous Thu 01 Nov 2012 05:56:35 No.5212768 Report

Quoted By:

potato

Anonymous

Anonymous Thu 01 Nov 2012 06:05:39 No.5212798 Report

Quoted By:

>>5212712
Shake'n'Bake... eXXtreme!

Anonymous

Anonymous Thu 01 Nov 2012 06:18:35 No.5212833 Report

Quoted By: >>5212888

>>5209640
>First time on /sci/
>See 159 post thread about cooking steak with atmosphere.
>Lolwut

Anonymous

Anonymous Thu 01 Nov 2012 06:32:41 No.5212885 Report

Quoted By:

>>5212642
If we do it correctly, it will hit terminal velocity right after it is cooked to it's maximum temperature. We could easily catch it in a net then. If we have it in an apparatus, then we can just design a parachute to come out of the apparatus.

Anonymous

Anonymous Thu 01 Nov 2012 06:32:48 No.5212888 Report

Quoted By: >>5212894

>>5212833
don't get your hopes up, it's usually just trolls, homework threads, and discussions of what would happen if a sun made of lava and a sun made of ice collided

Anonymous

Anonymous Thu 01 Nov 2012 06:35:13 No.5212894 Report

Quoted By: >>5212967 >>5212983

>>5212888
WHAT WOULD HAPPEN THOUGH

Anonymous

Anonymous Thu 01 Nov 2012 07:16:32 No.5212967 Report

Quoted By: >>5212983

>>5212894
i dunno, make a thread about it, see what the rest of /sci/ thinks

Anonymous

Anonymous Thu 01 Nov 2012 07:31:46 No.5212983 Report

Quoted By: >>5212993

>>5212894
>>5212967
No need, you cant have that much material in one place and have it maintain its composition as water or lava. The sun is not made out of special sun dust its just matter compressed to the point of fusion the same would happen with a sun sized nug of ice (water) or rock/lava.

Anonymous

Anonymous Thu 01 Nov 2012 07:42:02 No.5212993 Report

Quoted By:

>>5212983
But the heavy atoms couldn't fuse, so would it collapse into a black hole?

Anonymous

Anonymous Thu 01 Nov 2012 08:01:28 No.5213040 Report

Quoted By:

You're all forgetting that the thermosphere is hot enough to cook steak already.

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