Life Definition and 1000 Threads

Please help me solving this homework! 1. List three reasons why knowing the speed of sound is important to your life? 2. From at least three sources, gather information on how you can measure the speed of sound. then, describe the methods that are available to you. Information can be...

I am an older person (30 +) that has worked in technology for nearly 20 years. I have worked on and with High Performance Technical computing clusters to support NASA and scientist. I have no degrees. I have always has a deep interest and enjoy Astronomy, Physics, Cosmology. I am...

How does the temperature of a star relate to the radius of a star? How does the mass of a star affect the temperature of the star's core? How does the luminosity of a star relate to how long a star will live? How do the spectral lines of a star determine if the star is a first generation...

Hi all, I'll be starting my final year of my undergraduate degree in pure mathematics next year. My intention is to do postgraduate work and then try to get a position as a research fellow. However, I don't really know what a research mathematician does on a day to day basis, I just like the...

HI all. Just looking for some ideas or pointers. I wish to pass on an idea to a friend. I want to look at Platonic shapes in 3D evolving through various iterations. I've played with pretty fractals and I've played with the 2D and 3D Game of Life games. both nice diversions :) on a rainy...

Earth first formed about 4.6 billion years ago, condensing out of the gases & dust in the proto-Sun's Planetary Disk. But, for about the 1st billion years, the proto-planet was repeatedly pummeled by swarms of Impactors. They deposited gargantuan quantities of energy onto the Earth's surface...

Hey PF, I want to resurrect an old robot radio I have sitting around. What exactly is involved with building an AM/FM receiver?

So I like physics a lot and think that I would probably like to get my PhD but I have some concerns. One of the big ones is being able to have a social life while working on my PhD. If it was a degree that only took like 2 years to get I wouldn't be so concerned but considering that if I do...

Bigger stars are significantly brighter. That pushes back their Habitable Zones (HZs), where D2 ~ L, which makes them look smaller in the skies of (hypothetical) habitable planets, whose years are also a lot longer: Type Mass Temperature Radius Luminosity HZ-Distance Apparent-Size HZ-Year...

Assuming we can ever find another habitable planet and can get there, how the heck would we start to colonise it. If there is water, vegetation and there is~the same climate of Earth.

I am currently a junior at a 4 year university and I will be graduating in the spring of 2010 with a BS in physics. I'm having a very hard time deciding what to do after I graduate, so I thought I'd ask around for ideas. My problem is that I have a lot of interests, but I don't know how to...

1. Death 2. Taxes 3. To make continued substantial contributions (in anything) in the long term, one must work very hard. Agreeable?

The problem statement An electron going from 2p to 1s state in hydrogen sits up at the 2p for a while then jumps down. with the given eqn W=\frac {4*\alpha*\omega^3}{3*c^2}*\mid r12\mid^2 \mid r12\mid^2=\mid<1\mid x\mid2>\mid^2+\mid<1\mid y\mid2>\mid^2+\mid<1\mid z\mid2>\mid^2 alpha is...

If one wants to live a LOOOONG life doe's it matter what one eats and drinks? I recon it is all in the mind set, if one doe's not want to kick the bucket one will endure, just so long as some thing doe's not come along and throw a spanner in the works.

Can somebody give me an idea what you get upto on a day to day basis? I know roughly what you work towards in a PhD, obviously it depends on your topic, but I have no idea what it consists of day in and day out. For example, what maths do you do daily? What theory do you do daily? How much...

Now available on line through Google: http://images.google.com/hosted/life Images from the Civil War forward. They will have 107 images eventually.

I thought this internet application created by http://lindenlab.com/" was interesting: http://en.wikipedia.org/wiki/Second_life http://secondlife.com/ It takes the idea of a video game to an extreme. Video games normally either capture some specific portion of real life (i.e. life...

Why is life not included as a separate (fifth) fundamental force of nature? I’ve heard it said that life is more efficient at transforming energy (moving things around) than nuclear energy. This would seem to imply a force that is separate from the other 4. (I’m not necessarily talking about a...

It may sound trite, but people keep asking it. So, what is the meaning of life?

That is, if these cells even had anything to do with it. We're only going by the endosymbiotic theory.

is the chances pretty rare that advanced and intelligient life exists somewhere else in our universe, I mean it seems like we got pretty lucky here on Earth to get these conditions to have such abundant life. I am not doubting that bacteria and other simpler organisms exist elsewhere but it...

Draught-board 8x8. 12 pieces on each side that may only move forward but capture forward and backwards. Only when a piece is kinged it may move backwards. If a jumping move (beating) is available, that move must be made even if other non-jumping moves are available. A player wins by capturing...

I've always wondered what a day in the life of an academic is like, particularly mathematicians, philosophers, and most of all theoretical physicists. So what's an average day like for a theoretical physicist? Do you sit in your thinking chairs, lost deep in thought, trying to unwind...

The first brains came about in the precambrian or at the border with the cambrian around 560 million years ago when the first multi-celluar organisms emerged. It has always struck me how/why organisms developed brains. The brain must have emerged together with eyesight, since eyesight would be...

Say you map out the entire decision tree of an individuals life starting from birth. Each node has N branches, where N is very large, and delta t approaching zero. Let's keep it finite density because we want some results. Now you trace out the individuals realized path outcome amongst...

If someone dies in a hospital a member of medical staff tries to brings their heart back to life, sometimes this works. Why if someone dies of nateral causes can't their heart be braught back to life after a while?

If the nuclear fusion reaction of converting 4 H ! He occurs at an efficiency of 0.7%, and that mass is converted into energy according to the equation E = mc2, then estimate the Main Sequence lifetime of the Sun (spectral type G2) in years if the luminosity of the Sun is 3.83×1033 ergs s−1...

how do you delete posts? i was going to post a question and i accidentally posted it how do i delete this error?

Hey guys, I know that PF posters often say to search, so I did that. I found that like 99% of the forum listed engineering as a major that required ALOT of the students time. However, I was wondering if we could put some numbers to this idea, I don't think that will be much of a problem since...

If you find PF a benefit to your life please consider upgrading your account CHILL OUT! Does everyone get this or does it track the amount of time you've been a memeber, post count, activity level? lol.

Here in Georgia we are awaiting action by authorities to execute a young black man, Troy Davis for murder to which he has never been linked by any hard evidence of any kind. Although 9 eyewitnesses once implicated him, 7 of them now say otherwise, some say they were pressured by police to lie...

A smaller number of entries this week, which is expected considering the difficult nature of the theme. This week, the theme is on live performance by performing artists. Please vote for the picture that best represents our theme. 1. Integral 2. turbo-1 3. ZapperZ 4. Marzena...

I've been this way for several months now. A year ago, I'd have splurged my money on everything. Mostly electronics and science gadgets. Now the only thing I really want, and barely, is knowledge. My money is starting to build up more than I've ever had before. Which I can put away for the...

[FONT="Comic Sans MS"][SIZE="5"]Life Is A Stage This week, the theme is on performers. Your picture must have, as its main subject, performing artists. This can be musicians, actors, dancers, etc. performing for the public or an audience. Please note that if the photo came from a...

Homework Statement How does life violate the 2nd law of thermodynamics? Homework Equations The 2nd law states that with ever energy transformation entropy increases. The Attempt at a Solution I am not sure where to begin with this. All I can think of is as we evolve our system...

Hi, I had made an inquiry about regression last week and am still working on understanding the whole concept.This week my question is different. How would I use the a and b values of the regression to indicate how something is growing. Like I'm having problems interpreting data because I do not...

This promises to be a difficult contest to vote on since there are so many wonderful pictures. Still, please pick the picture that best represents our theme, which is on trees. Note that the participants were asked to submit a photo that has the tree/s as THE main subject, and not the scenery...

[FONT="Comic Sans MS"][SIZE="5"]The Tree Of Life This one should be easy. Pictures this week must be on trees. Trees (or a tree) must be the main subject of your picture, not the background scenery, the people in front of it, or anything else. Please note that fake trees do not qualify...

http://www.spr.ac.uk/JSPRabstracts.php3?year=2000#oct This case concerns a young boy in Sri Lanka who made several statements regarding a previous life, among them where he had lived and how he was killed when traveling in a truck through a forest. The boy associated two birthmarks with his...

QoL,Location,Pay,especially what do you do for work? I'll listen for now and will chime in later..

I bought a fairly cheap wireless mouse a while back. With the batteries it came with it lasted quite some time, at least a few months, before it died. I bought new batteries from the store that were on sale and put one in. About a week later I found that the usb plug had come detached from...

Hi All, We have manufactured a custom bolt (similar to standard bolt). Now we need to calculate the fatigue life of the bolt. Could you please guide me in calculating the fatigue life? Thanks, Ana

Rather bored, so I was just wondering - only considered generalizations with the underling principle here, but I'm looking for specifics: have your interests in physics/mathematics altered your love life in any way? Say, have you pissed your significant other off with your obsession with...

Do any of you get this channel? Have you seen the show "Get Out"? It's a travel show where these three girls travel around the world and tell you about it. Oh, and they only wear bikini tops and they only go to tropical areas. I can't get enough of this show. It is so sexist, because these girls...

Hi, I was having a discussion with a friend about the probability of life in the universe outside of earth. From what i know, there are 70 000 000 000 000 000 000 000 stars and god knows how many planets. Given the low probability of life spawning on a single planet but the huge amounts of...

I am on a computer at a public library, and I only have fifteen minutes left. So this post definitely won't be as well-polished as most of my posts. I am interested in living a simple life out in the country. I want to buy some land out in the country and build a cabin on it. I could heat...

Thought this would be an interesting topic. so just in everyday life, what sort of stuff have you applied the tool K = 1/2 mv squared for?

I wrote something which I believe gets to the origin of fashion and gossip in a simple and logical way. I would be happy with any comment on whether it makes sense to you or not. Why do women find it important to be in on the latest fashion trends and gossip? Fashion's use couldn't be just...

Researchers think they have found traces of ammonia in Mars' athmosphere. Since ammonia is degraded quickly there, if this were true, it would mean the presence of some ammonia-producing source on Mars. THe best bets for that would be either active volcanoes or microbes, but since active...

Interesting publication: http://www.chemie.de/news/e/84187/ In normal geology jargon, this means that they are pretty convinced to be on to something. However: What they found was depletion of heavy 13C atoms reducing the d13C ratio to values comparable to photosynthesis nowadays as...