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### Re: What is the mass of a feather?

Posted: **Wed Mar 25, 2009 11:29 pm UTC**

by **puetzk**

ArmonSore wrote:I take the same stance here. It's not wrong to say that a feather is accelerating, but it's not right either. It's unprovable(which sounds to me to be a very godelian statement). So we needn't say that the feather is accelerating at all. For example, if we're in a spaceship that is accelerating upwards at 9.8 m/s^2, and we drop a feather, we can't tell the difference between doing the same experiment on earth. Which is to say, the feather does the same exact thing as it does in a vacuum near the earth's surface. So you can talk about either as being true, if you want to.

But this bothers me a little bit. My above argument seems to break down since we "know" that we're in a gravitational field, not free space. If it is impossible to tell the difference then how do we know this to be true? Does someone have an answer to this? Is there a completely consistent way to view our experience on earth as not being due to a gravitational field?

I believe the key here is that earth's gravitational field is non-uniform - it weakens with distance, and points toward the center of the earth. These variations in strength and vector differentiate it from what would be observed if Earth were accelerating (at least if we are able to correlate experiments conducted in different portions of the field), and indicate that it is in fact gravitational in nature.

### Re: What is the mass of a feather?

Posted: **Fri Apr 10, 2009 11:11 pm UTC**

by **scikidus**

Place the feather (with a mass of x kg) inside a massless box with a massless matter teleporter (to remove the feather to the netherworld randomly), and close the box. Quantum uncertainty states that the feather both does and does not exist, and therefore the box simultaneously has a mass of 0 and x kg.

Place this box inside another massless box with another massless matter teleporter, and close the outer box. By the same process above, this box simultaneously has a mass of 0, 0, 0 and x kg.

Repeat the above process an infinite number of times. As more and more boxes are added, the probability that the feather is massless approaches one. Therefore the feather has no mass. QED.

----------------

Step 1: Prove the Riemann Hypothesis.

The proof of the relevance of this step to the calculation of the mass of a feather is left as an exercise to the reader.

----------------

The mass of a feather (x kg) over time is constant. The derivative of any constant is zero. Therefore, the mass of a feather is any constant, or C. QED.

----------------

Galileo showed that all objects fall at the same rate. Obviously, therefore, all objects have the same mass. QED.

### Re: What is the mass of a feather?

Posted: **Tue Nov 17, 2009 3:07 pm UTC**

by **bigeasy**

3clipse wrote:Citizen K wrote:

In ancient Egypt...

One soul, more or less.

And I remember some reading about some scientist or another who once tried to weigh souls as they escaped dying people (don't remember all the details offhand). So find those numbers and use them. Or go collect your own data.

Although the internet sources I've read say the people lost 21 grams after death. I distinctly remember a book mentioning this experiment and saying that the bodies

gained 21 grams after death. As if the souls dragged the bodies toward hell as they departed. Maybe we should retry the experiment with "better" people as opposed to possible sinners.

### Re: What is the mass of a feather?

Posted: **Tue Nov 17, 2009 4:51 pm UTC**

by **Soralin**

puetzk wrote:I believe the key here is that earth's gravitational field is non-uniform - it weakens with distance, and points toward the center of the earth. These variations in strength and vector differentiate it from what would be observed if Earth were accelerating (at least if we are able to correlate experiments conducted in different portions of the field), and indicate that it is in fact gravitational in nature.

Hey, there's a good question: What's the difference in weight between a feather standing on end, and the same feather laying flat on a surface?

### Re: What is the mass of a feather?

Posted: **Wed Nov 18, 2009 2:12 am UTC**

by **Sriad**

The best solution may also be the simplest:

1: Collect, clean, and count every feather.

2: Pulverize the feathers into a fine powder and dissolve in a solvent of known density.

3: Completely fill a hollow sphere of known mass (edit, and inner radius) with the feather solution

4: Place the sphere at the center of the Earth.

5: Measure the change in Earth's gravity, and with a few trivial calculations we have established the weight of one feather!

### Re: What is the mass of a feather?

Posted: **Sat Nov 21, 2009 6:29 am UTC**

by **pubescent tuba**

What everyone seems to have missed is that the very process of measuring the mass of a feather, assuming we can manage that in one of the ways these most wonderful mathematicians suggest, changes the thing being measured at the quantum level, so we can never be sure what the mass was before the measurement.

Therefore, the only possible way to find the mass of a feather is to define it as 1fmu, as has already been suggested.

### Re: What is the mass of a feather?

Posted: **Sat Nov 21, 2009 10:54 pm UTC**

by **BlackSails**

Thats not how quantum mechanics works.

### Re: What is the mass of a feather?

Posted: **Sun Nov 22, 2009 12:41 am UTC**

by **YoungStudent**

This thread is hilatous!

### Re: What is the mass of a feather?

Posted: **Sun Nov 22, 2009 12:58 am UTC**

by **You, sir, name?**

BlackSails wrote:Thats not how quantum mechanics works.

Well, you -could- change it's mass if you use some destructive means of observing it. And if you want high enough precision to count how many atoms it's made up of, you're pretty limited.

### Re: What is the mass of a feather?

Posted: **Tue Nov 24, 2009 9:49 pm UTC**

by **PhoenixEnigma**

Soralin wrote:puetzk wrote:I believe the key here is that earth's gravitational field is non-uniform - it weakens with distance, and points toward the center of the earth. These variations in strength and vector differentiate it from what would be observed if Earth were accelerating (at least if we are able to correlate experiments conducted in different portions of the field), and indicate that it is in fact gravitational in nature.

Hey, there's a good question: What's the difference in weight between a feather standing on end, and the same feather laying flat on a surface?

What's the length on the feather, and the mass distribution as a function of distance from a defined point on the feather? Also, to be complete, the date, time, and location, so that we can take into account tidal effects of at least the Moon, and ideally the Sun and Jupiter as well.

### Re: What is the mass of a feather?

Posted: **Mon Nov 30, 2009 9:54 am UTC**

by **Waylah**

I can't believe this thread is FIVE PAGES LONG! That is hilarious. My fave reply is

meat.paste wrote:No, no, no. The answer is easy and obvious. Define the mass of the feather to be 1 unit of mass. Finished.

(It's someone else's job to calculate the conversion factor into other units.)

### Re: What is the mass of a feather?

Posted: **Mon Nov 30, 2009 12:49 pm UTC**

by **You, sir, name?**

Waylah wrote:I can't believe this thread is FIVE PAGES LONG! That is hilarious. My fave reply is

meat.paste wrote:No, no, no. The answer is easy and obvious. Define the mass of the feather to be 1 unit of mass. Finished.

(It's someone else's job to calculate the conversion factor into other units.)

You must be new here. Welcome to the internet.

### Re: What is the mass of a feather?

Posted: **Thu Dec 03, 2009 3:01 am UTC**

by **MisterCheif**

pubescent tuba wrote:What everyone seems to have missed is that the very process of measuring the mass of a feather, assuming we can manage that in one of the ways these most wonderful mathematicians suggest, changes the thing being measured at the quantum level, so we can never be sure what the mass was before the measurement.

Therefore, the only possible way to find the mass of a feather is to define it as 1fmu, as has already been suggested.

I propose the that it be one feather unit, instead of feather mass unit.

### Re: What is the mass of a feather?

Posted: **Mon Dec 14, 2009 5:48 am UTC**

by **π=3.15**

Weigh yourself, eat the feather, weigh yourself again.

### Re: What is the mass of a feather?

Posted: **Mon Dec 14, 2009 5:59 am UTC**

by **You, sir, name?**

π=3.15 wrote:Weigh yourself, eat the feather, weigh yourself again.

But how would you weigh yourself?

I propose design an experiment that works like this:

1. You jump in a vat of acid, dissolve yourself, then it weighs the acid.

2. The machine drops the feather into the acid, and it dissolves, and it weighs the acid again.

3. The machine calculates the difference, and posts it online for posterity.

It works since you dissolved in acid + feather dissolved in acid would be equivalent to you having eaten the feather and then dissolving yourself in acid.

### Re: What is the mass of a feather?

Posted: **Mon Dec 14, 2009 10:45 am UTC**

by **smw543**

Meteorswarm wrote:Why not simply ask the feather?

Because that's terrible etiquette, of course.

### Re: What is the mass of a feather?

Posted: **Sat Jan 23, 2010 3:51 am UTC**

by **sinal**

put the feather in a cup of water filled to the brim and measure the amount of water that splashes out.

### Re: What is the mass of a feather?

Posted: **Sat Jan 23, 2010 4:16 am UTC**

by **scikidus**

sinal wrote:put the feather in a cup of water filled to the brim and measure the amount of water that splashes out.

Even without surface tension issues for the water (just add a dab of soap), that measures the volume of the feather through displacement. You still need to know the density of the elusive feather molecule (2

Fe+2

At+

H_{2}+2

Er --> 2FeAtHEr)

### Re: What is the mass of a feather?

Posted: **Sat Jan 23, 2010 7:05 am UTC**

by **ocdscale**

Shouldn't feathers have negative mass because birds float in the air?

### Re: What is the mass of a feather?

Posted: **Sat Jan 23, 2010 6:56 pm UTC**

by **You, sir, name?**

ocdscale wrote:Shouldn't feathers have negative mass because birds float in the air?

They shouldn't. That would mean that a feather is the absence of the opposite of a feather in a periodic lattice of the opposite of a feather-like things. Like a

hole is the absence of an electron.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 3:31 pm UTC**

by **rho**

ocdscale wrote:Shouldn't feathers have negative mass because birds float in the air?

Yeah, you're confusing feather mass with

effective feather mass.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 9:30 pm UTC**

by **Turtlewing**

method 1:

If we accept the many world interpretation it should follow that there exist a universe wherin you aleady know the mass of a feather. Problem solved by quantum-feather-massing.

method 2:

Step 1: create a universe simulator

Setp 2: determine initial condioions of the universe

Step 3: using the initial conditions of the universe determined in step 2 run a simulation of the univers on the simulator created in setp 1.

Step 4: examin the data-representation of all feathers which are produced on Earth, and calculate the mean value of their masses.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 9:36 pm UTC**

by **You, sir, name?**

1) Determine the wavefunction [imath]\psi[/imath] of all matter in existence.

2) Apply the time-evolution operator to get it's value in the present.

3) Find the feather-operator so that [imath]\hat{F}|\psi> = F|\psi>[/imath], where F is the quantum feather number, which scales ||\psi||^2 from the probability to find any matter, to find a feather.

4) Find [imath]<\psi|\hat{F}|\psi>[/imath]

5) Collect all feathers in existence.

6) Weigh them

7) Divide by the value you got in (4)

Though I'm not sure if the best way. You may need to develop quantum feather field theory (or quantum featherdynamics).

Penguin diagrams seems an appropriate aid, though I'm not sure how it fits in the theory just yet.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 10:09 pm UTC**

by **BlackSails**

You cant determine the wavefunction of all matter in existance.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 10:19 pm UTC**

by **You, sir, name?**

BlackSails wrote:You cant determine the wavefunction of all matter in existance.

Have you tried?

If this is true, it might imply that it's impossible to determine the mass of a feather. Maybe the F-operator and the mass operator are incompatible observables.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 10:34 pm UTC**

by **Ended**

I stopped on my way back to my apartment to visit some friends living in Meyrin where I smoked some illegal substance. Later, when I got back to my apartment and continued working on our paper, I had a sudden flash that the famous diagrams look like penguins.

Research: I think I'm doing it wrong.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 10:50 pm UTC**

by **BlackSails**

You, sir, name? wrote:BlackSails wrote:You cant determine the wavefunction of all matter in existance.

Have you tried?

I dont need to, there are many reasons it is impossible. To start with, you need to be able to represent arbitrary real numbers in whatever you are writing the wavefunction down in.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 11:09 pm UTC**

by **You, sir, name?**

BlackSails wrote:You, sir, name? wrote:BlackSails wrote:You cant determine the wavefunction of all matter in existance.

Have you tried?

I dont need to, there are many reasons it is impossible. To start with, you need to be able to represent arbitrary real numbers in whatever you are writing the wavefunction down in.

Couldn't that also be used to argue that transcendental functions are impossible?

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 11:12 pm UTC**

by **BlackSails**

They are certainly impossible to physically realize. If you take any circle, any circle at all, and measure it, you will find that the ratio of circumfrence to diameter terminates.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 11:15 pm UTC**

by **You, sir, name?**

BlackSails wrote:They are certainly impossible to physically realize. If you take any circle, any circle at all, and measure it, you will find that the ratio of circumfrence to diameter terminates.

But you can't dismiss the possibility of such a representation existing for our mystery wavefunction. Furthermore, the as of yet undefined feather operator might have some effect that makes it more manageable, and symmetries may make the integration at least hypothetically possible. We also only need it to a similar order of certainty as the number of feathers in the earth (that we can posit is finite), so some form of incremental numerical approximation might ease the calculations.

### Re: What is the mass of a feather?

Posted: **Mon Jan 25, 2010 11:24 pm UTC**

by **BlackSails**

The point Im trying to make is that you need to find a point, a single point in phase space that represents the entire universe. And you cant do that with infinite precision. You can get really, really close, but your system will diverge from the universe.

### Re: What is the mass of a feather?

Posted: **Tue Jan 26, 2010 12:02 am UTC**

by **You, sir, name?**

BlackSails wrote:The point Im trying to make is that you need to find a point, a single point in phase space that represents the entire universe. And you cant do that with infinite precision. You can get really, really close, but your system will diverge from the universe.

I see your point. But let us not forget, this is physics. Now is the time we break out the approximations. First of all, we can argue that the outer space is a medium which feathers can impossibly traverse (as there are no birds in space), and therefore argue that the solar system is a closed system for feathers. Furthermore, we can argue that feathers only exist on the surface layer of the earth, and not inside it, or indeed, on other celestial bodies. So we can approximate the universe as a spherical shell, greatly reducing the complexity of the required wavefunction.

### Re: What is the mass of a feather?

Posted: **Tue Jan 26, 2010 4:42 am UTC**

by **Outchanter**

The OP asked for the average mass, so this is clearly a statistics problem. First, interview everyone on this thread for their belief regarding the mass distribution. This will yield a subjective Bayesian prior. In addition collect everyone's Netflix movie preferences, e.g. whether they enjoyed Hitchcock's Birds.

Then go out and randomly sample feathers from a variety of birds, not neglecting to record the birds' Netflix preferences, as well as species, height, weight, diameter (assuming a spherical bird), and number of eggs laid as a function of time. Use this to calculate a posterior distribution which allows you to recommend movies to birds based on feather weight, while simultaneously demonstrating that global climate change makes the spherical bird assumption unreliable.

### Re: What is the mass of a feather?

Posted: **Mon May 17, 2010 1:12 am UTC**

by **tmim**

evilbeanfiend wrote:to find the mass of the feather simply find the mass of everything but the feather and subtract from the mass of the universe.

How are you meant to find the mass of the universe.

meat.paste wrote:I think the best way would be to find a cosmic string. To the string, attach a magnetic monopole on one end and a naked singularity on the other. Excite the string with the feather. Count how many universes are spawned. Then find the energy in each of these universes. Since the total energy comes from the feather motion, use the kinetic energy to find the mass. This would require measuring the velocity, though, and that might be tricky.

but don't universes have zero energy as the mass energy cancels out the negative gravitational energv

### Re: What is the mass of a feather?

Posted: **Mon May 17, 2010 4:55 pm UTC**

by **redearth1210**

If I had to make just a random guess on how to do this, get a bird, posion it so it stays still, and use displacement to get the mass. Remove the feathers, and find the new mass. Take the change in mass, and divide it by the number of feathers removed.

Of course, this doesn't take dirt and grime into account, nor lost cells, so I believe a better solution is in proposition.

Like counting the molecules.

### Re: What is the mass of a feather?

Posted: **Mon May 17, 2010 6:22 pm UTC**

by **WarDaft**

You're all needlessly overcomplicating this.

The mass of a feather is obviously 42.

How did that take this long?

### Re: What is the mass of a feather?

Posted: **Mon May 17, 2010 7:26 pm UTC**

by **You, sir, name?**

WarDaft wrote:You're all needlessly overcomplicating this.

The mass of a feather is obviously 42.

How did that take this long?

That's quite preposterous. "42" has no unit.

### Re: What is the mass of a feather?

Posted: **Tue May 18, 2010 10:24 am UTC**

by **mrbaggins**

It's clearly 42fu^{-1}.

fu, of course, being a feather unit, equal to the mass of 42 standard feathers.

### Re: What is the mass of a feather?

Posted: **Tue Jun 01, 2010 9:37 am UTC**

by **Argency**

If you're going to accelerate the feather under a continuous force, shielded from all other energy sources, in a vaccuum, under microgravity, preventing any rotation, it's important to remember that the feather you use for your measurements has to be completely symmetrical on all axes, or the Casimir effect will act more on one side than on the other.

### Re: What is the mass of a feather?

Posted: **Wed Jun 09, 2010 6:54 am UTC**

by **wingdaddy**

There is no feather. What we know as "feathers" were created by the architect in the matrix.