My FTL Challenge

[sjastro]

After.

As I understand it, heat is the total amount of kinetic and potential energy in an object, whereas temperature is the average amount of heat.

So pouring room-temperature cream into a cup of hot coffee, then leaving to answer the phone, will give the coffee time to reach thermal equilibrium between the coffee and the cream.

Unless, of course, I'm wrong.

Before.

The basic physics of heat provides the answer: you should add the cream to your coffee before answering the phone. Coffee with cream cools about 20% slower than black coffee, for three reasons:

1. Black coffee is darker. Dark colors absorb heat faster than light colors (just think about wearing a black T-shirt versus a white T-shirt on a hot, sunny day). But dark colors also emit heat faster than light colors. Absorption and emission are essentially two sides of the same coin. So by lightening the color of your coffee, you slow its rate of heat loss slightly.
2. Stefan-Boltzmann says so. The Stefan-Boltzmann law says that hotter surfaces radiate heat faster specifically, the power of emission is proportional to the temperature (in kelvin) raised to the fourth power. So let's say you have two cups of coffee that start at the same temperature. You pour cream in cup #1 and the coffee drops in temperature immediately. But the rate at which it loses heat also drops. Meanwhile, the hotter black coffee in cup #2 cools so rapidly that within five minutes the two coffees are at about the same temperature. But you still haven't added the cream to coffee #2! When you do, it cools even more; cup #1 is now the hotter of the two.
3. Viscosity versus evaporation. This is the clincher. Adding cream thickens the coffee (adds viscosity), so it evaporates slower. You'd be surprised just how much heat evaporation carries away. Slow the rate of evaporation and you avoid a lot of that heat loss. (This is also one big reason that coffee stays warm longer with a lid on the cup.)

The point is the answer requires a knowledge of science, not a personal opinion and certainly not living in a make believe world where anything is possible but in reality science limits the options.

 

[sjastro]

How could you have possibly predicted the response sooo accurately there?
We need answers to that question!

This is a case where "science can take a hike" as I hate coffee.
It's on my forbidden list (like the Catholic church list of forbidden books) and includes all seafood, all diary dairy products, all freshwater crustaceans, alcohol and in particular anchovies.

 

[AV1611VET]

It's on my forbidden list (like the Catholic church list of forbidden books) and includes all seafood, all diary products, all freshwater crustaceans, alcohol and in particular anchovies.

The only diary product I'm interested in is God's diary: the Bible.

 

[sjastro]

The only diary product I'm interested in is God's diary: the Bible.

Fine a typo unless you think the Bible is edible which in your case wouldn't surprise me in the least.

 

[SelfSim]

This is a case where "science can take a hike" as I hate coffee.
It's on my forbidden list (like the Catholic church list of forbidden books) and includes all seafood, all diary dairy products, all freshwater crustaceans, alcohol and in particular anchovies.

Even so, it was a fair question: a 50/50 chance of getting it right in the absence of such knowledge .. But alas .. 'twas not to be!

 

[RileyG]

No.

 

[sjastro]

Even so, it was a fair question: a 50/50 chance of getting it right in the absence of such knowledge .. But alas .. 'twas not to be!

Guessing the answer is not terribly productive.
Those of us old enough to remember Professor Julius Sumner Miller making Cadbury ads on Australian TV commented on the problem.

You put the cream in before you answer the telephone.
This problem is very very complicated thermodynamically and 200 pages could be written on the physics of it. Which shows that simple matters are not trivial. For our purpose here it is sufficient to say adding the cream first lowers the temperature of the whole system at once, whereupon the rate of heat loss is lessened. That is, the cooler the system the less fast it loses its heat. There are at least twenty more parameters-variables-elements-that enter this discussion. Can you name a few?

Pascal's paradox.

Explanation of the paradox.

 

[SelfSim]

Guessing the answer is not terribly productive.
Those of us old enough to remember Professor Julius Sumner Miller making Cadbury ads on Australian TV commented on the problem.


Pascal's paradox.

Explanation of the paradox.

A classic by a legend!

So many gems in that 2nd one, including: 'Nature is absolutely dependable ... It is man who fails' (3:00min).

None of his traditional: 'Watch! .. watch! ... watch! ... watch!', though.

 

[durangodawood]

A team of scientists learn to beam an object from Earth to Planet Timbuktu, sixteen million lights years away, in 1/10 of a second.

Would you nominate them for a Nobel prize?

If we determine that planet Timbuktu shouldnt be called a "planet", could they still beam the object there?

 

[AV1611VET]

If we determine that planet Timbuktu shouldnt be called a "planet", could they still beam the object there?

Not legitimately.

 

[sjastro]

A classic by a legend!

So many gems in that 2nd one, including: 'Nature is absolutely dependable ... It is man who fails' (3:00min).

None of his traditional: 'Watch! .. watch! ... watch! ... watch!', though.

Using physics to sell chocolate.

From what I recall this caused a crisis in Australian households as removing the egg from the bottle without breaking the glass was an issue.

 

[Kylie]

Not legitimately.

Kirk: Scotty! I want you to beam me, Spock, and McCoy over to the derelict spaceship to see if we can save the crew!

Scotty: I cannae do it, Cap'n! Th' transporter will only work if I'm beamin' ye to a planet! I simply cannae beam ye to a ship or anythin'!

 

[Moral Orel]

No it is a crime to be outside the lightcone when travelling faster than the speed of light as it violates causality and is the ultimate in rudeness for sending information which reaches its destination even before it has left Earth.
It's like turning up uninvited.

These dumb scientists should have realized being outside the lightcone is in the space-like ("Elsewhere") region of space-time where the future can occur before the past.

@AV1611VET made a comment in another thread that I find interesting. What if the object travelled via wormhole? Does that still break causality like traveling faster than the speed of light does?

 

[sjastro]

@AV1611VET made a comment in another thread that I find interesting. What if the object travelled via wormhole? Does that still break causality like traveling faster than the speed of light does?

You cannot travel through a wormhole (if they exist) faster than the speed light.
A wormhole is basically a short cut between two points in space-time.
Think of the universe as the surface of the Earth which is two-dimensional; to get to the point diametrically opposite you have to travel along the surface.
A wormhole in this case is a three dimensional passage way which passes through the Earth to reach the opposite side.
A light beam travelling through this passage way will take less time compared to light travelling along the surface, not because it is travelling any faster but rather it travels a shorter distance.

 

[Kylie]

@AV1611VET made a comment in another thread that I find interesting. What if the object travelled via wormhole? Does that still break causality like traveling faster than the speed of light does?

My (admittedly limited understanding) is that travelling through a wormhole does not mean you are moving through your local space faster than light.

Let's say I have a wormhole, one end of which is in my living room and the other end is on Planet Vulcan (I've always wanted to see Mount Seleya), which is 16 light years from Earth. From my point of view, the wormhole is a tunnel, but it does not need to be 16 light years long. The passage may be quite short, perhaps 10 meters. A good way of thinking about it is to imagine a piece of paper with two dots on it, one labelled Earth and the other dot, way over on the other end of the paper, labelled Vulcan. You can fold the paper so that the two dots are very close to each other. If you were an ant crawling on the surface of the paper, this folding wouldn't make any different to you - you'd still have to crawl all the way along the surface of the paper. But if someone got a short length of straw and punched through the paper so the straw created a tunnel between Earth and Vulcan, you could walk through the straw instead and find yourself at Vulcan after travelling a much shorter distance.

Likewise, space could be folded so that planet Vulcan was much closer to Earth. If we were travelling by rocket, then that would be like the ant crawling along the surface of the paper. We'd still have to travel the entire 16 light years. The fact that space was folded so Vulcan was nearer to Earth would make no difference, because that folding would be in a dimension we can't make use of. (In the paper analogy, the ant is confined to the two dimensional surface of the paper, but the folding takes place in the third dimension.)

But if we could access this other dimension, we would cross the small gap through the wormhole. We wouldn't be violating causality, since we aren't moving through space faster than light. I could walk through the wormhole at a normal walking speed and still get to Vulcan in a few seconds.

 

[AV1611VET]

Likewise, space could be folded ...

Revelation 6:14a And the heaven departed as a scroll when it is rolled together;

 

[AV1611VET]

A light beam travelling through this passage way will take less time compared to light travelling along the surface, not because it is travelling any faster but rather it travels a shorter distance.

Yup.

We could see a star a jillion light centuries away, whose light left it a moment ago.

 

[Yttrium]

Yup.

We could see a star a jillion light centuries away, whose light left it a moment ago.

A moment ago?

That would fry the Earth!

 

[Moral Orel]

Yup.

We could see a star a jillion light centuries away, whose light left it a moment ago.

Nope. The path that light traveled isn't a jillion light centuries long, so the star isn't a jillion light centuries away.

 

[AV1611VET]

Nope. The path that light traveled isn't a jillion light centuries long, so the star isn't a jillion light centuries away.

The light we're seeing from SN1987A could have left yesterday, if God so willed it.