Life Definition and 1000 Threads

High School senior confused in life... :( :confused: I was wondering if anyone had any insight as to which career path I should take? I am interested astronautical engineering, because of my love of space and designing spacecraft seems incredibly interesting and fun... It would be a...

Suppose the men in a country have a mean life span of 79 with a standard deviation of 8. And the women in the country have a mean life span of 83 and also a standard deviation of 8. Furthermore, suppose the life spans are normally distributed. What is the mean life span of the entire...

Moon rocks containing uranium 238, decays to lead with a half life of 4.5 billion yrs. The lunar rock sample you're invistigating contains half of the original uranium 238. How old is the rock? How would I go about solving this? What formula should I use?

Saw this on Monday morning: http://www.foxnews.com/scitech/2011/03/05/exclusive-nasa-scientists-claims-evidence-alien-life-meteorite/ My feelings on the validity of the findings are doubtful or inconclusive at best. Biology and extra-terrestrial life really aren't my expertise so I thought I...

Hello How can I calculate the fatigue life of a variable stress between 0 and 90 MPa in cast aluminum? Do I use the mean stress and compare it with the wohler curve? what is the logic of using the mean stress? Why not the maximum stress? Do I have to use the Goodman or Gerber diagram...

http://www.foxnews.com/scitech/2011/03/05/exclusive-nasa-scientists-claims-evidence-alien-life-meteorite/". Snippet:

http://www.foxnews.com/scitech/2011/03/05/exclusive-nasa-scientists-claims-evidence-alien-life-meteorite/ When you consider the intergalactic scale and that there are something like 3x10^24 stars it seems so probable that life would exist--even in more complex forms. I heard that other labs...

RedZone, Second Life IP Address Detection Tool, Runs Afoul of New SL Policy, EU Data In an odd turn of events that is all too common online these days, an ingenious system created for Second Life land holders to reduce incidents of harassment and abuse by malicious griefers has itself turned...

and would like some input. I've defined myself as an astrophysicist for several years now, and it's been my dream to study astrophysics from early childhood. I went to university shortly after high school, but dropped out halfway during my second semester, largely because of depression and...

Hi there, Someone asked me this earlier when we were talking about radioisotope dating. How do physicists determine the half lives of isotopes when said half life stretches into the millions of years? Random question I know :P -Dan

If you look at Earth 3000 years ago versus the Earth today there is now far more structure, ie cities, roads etc. It is less random, it has less entropy, and that is as a result of life. Especially intelligent life. Considering the solar system as a whole, does the decrease in entropy...

Hi, this is probably just going to be a rant , so turn away if you don't care: I'm taking math courses at my university right now, and I've been self studying math for about a year and a bit more now ( in high school, I only took math up to grade 10.. and it was "essentials" math, I was a bad...

What is meant by discharging capacitor half life (the description). I seem to be getting different description, I would just like for someone to confirm it here for me please.

Unusual paper: http://arxiv.org/abs/1102.1108 Some planets get ejected from their systems and wander off into interstellar space. The authors investigate what would be needed for such a planet to remain able to support ocean-floor life for a protracted period on the order of a billion years.

Check this out: http://edition.cnn.com/2011/TECH/innovation/01/19/smart.roads/?hpt=Sbin Tell me if this is anything more than retarded. I don't mean to sound insulting, but this cracked me up, that's how sad it is. There are so many problems with this, I don't even know where to begin. I'm...

So, if I'm a person who loves physics and has no problems with equations, but simply isn't very creative with mathematics and isn't exactly in love with it either, should I not pursue a career in physics?

The problem: A radioactive material has a half-life of 50ln2 years. If you add 5 grams per year to the material, how much material will you have after 5 years if you start with 100 grams? What I've done so far: t = ln2/k = 50ln2 k = 1/50 k = .02 A = A0e^-kt N = 100e^(-.02)(5) = 90 grams...

How to determine in a cast aluminum part its consumed fatigue life? Lets imagine I get a cast aluminum part that looks good, but I have no idea for how many km it has been used (automotive). Which kind of non destructive tests or methods could I use to determine the consumed fatigue life, and...

I just finished Peter Singer's book "The Life You Can Save". It deals with practical ethics in approaching the topic of extreme poverty in the world. Peter essentially argues that any money spent on non-essential items and services is morally wrong. That money could be spent helping save the...

What is he earliest time when life could form in the Universe? If it is infinite, there always are very ‘lucky’ regions. We need population III stars, with a very short lifespan. They explode and form clouds with higher metallicity (I assume it is not enough for solid planets?). So we have...

Hi there, As we know, many innovations and designs in science are based off the natural world. I was wondering if it would be possible to create an efficient process of energy transfer similar to how living organisms work, with their use of Enzymes, ATP, etc for relatively efficient energy...

Hi, I have a question something along the lines of Here is a low pass filter, when the resistor = R and the capacitor = C. There is a sinusoidal voltage input source (V1) and a voltage across the capacitor (V2). The transfer function is T(w) = V2/V1. Determine the |T(w)| and arg(T(w)) where...

I am looking at building a pair of third class levers out of materials found at the local hardware store to lift up some 500lb and 1500lb hulls. I have systematically gone through every option available to move these hull pieces out of the mold and I'm left with two: 1) Modify an "off the...

Hello there, new to the forums, but it looked like a good place with knowledgeable folks so I've decided to join! My topic today will be on Jupiters moon Europa. Its just to gauge others ideas on this moon and the chances of it sustaining, or having the potential to sustain life. The...

Why it is said that ARPES measures the lifetime of the injected photo hole? When photons with certain energy promote electrons from the initial state to the final state with kinetic energy then by knowing the photon energy one can simply determine the binding energy of the initial state: Eb =...

Guys I'm not antisocial or anything. Neither I'm I afraid of people. But I'm in a situation where I have no choice but to just say screw it and stop making friends and stuff like that (not forever though). The problem is, friends want to go out and hangout and invite one another to their party...

If you haven't watched it, can be found here: I watched the second time today and it was absolutely astonishing, didn't quite "get it" the first time. It pretty much explains how life originates. I don't think anything can be added to what the program wanted to convey. I would like to...

Is life most likely to start near greatest statistical mechanical order? For instance, DNA's extended regular structure might relate lowest entropy for its molecular weight. Is biochemical replication the antithesis of randomness? Does the apparent rarity of life in the universe reflect the...

Hi, all! As I'm new to biology and life science, I'm interested in the classification system of life. However it's hard for me to memorize those seemingly Latin words of all kinds of lives. For example, I've absolutely no idea what 'Escherichia' means in Escherichia coli. Do you know...

Just background info. haha sorry so long! If you have the time, please help me. Im 24. All my life I've been taught not to follow my dreams. I've been treated as a nuisance or the special one in the family and have been called stupid as a kid. I've always felt very aware of the intentions...

I am not sure on this, so hope someone can shed some light on this. What type of organism was thought to be among the first on earth? I am not sure if this is the right way to ask this :) Lets say if I wanted to see, or do tests on an organism, and my tests were related to doing tests on...

I honestly don't know what I want for myself, and I'm not getting any younger. I am 25 and I need to devise a plan for my life. Here's a brief history of my life. I graduated from a small engineering school in michigan with a double major in electrical engineering and physics in 2008. Then...

I know someone whose life has been badly affected because his father is a drunkard. That is one the reasons I'm against alcohol because I've seen it with my own eyes how it affects others' lives. There are too many accidents because people drive while drunk. Many other crimes also stem out of...

Questions regarding "Earth life came from Mars" - ? - Thanks Hey guys ans girls, Ok now i am not fully versed in this theory, but the basis is that the life on Earth started from a impact from a piece of mars, that contained organisms, that survived the impact, and started life on earth...

Hello all I was reading an article which claimed science did not have a definition for Life. that statement on face value i think is just plain wrong. I think the author may have ment that it didnt have a definition that everyone will perhaps agree on. I am a computer programmer and my crude...

All the buzz is that NASA has found out something important. http://www.nasa.gov/home/hqnews/2010/nov/HQ_M10-167_Astrobiology.html

As 'unnati D' stated, in the now locked thread, "i believe the concept of a separate life force, existing without d support of an atomic body is worth exploring." This caught my interest, and even if his views may seem misguided and somewhat chaotic, there is an interesting concept worth...

Thought I'd share a thought I had about a year or so ago while I was looking through a Hubble photos book in wonderment at the vast scale of the universe. Suppose our universe is but one in let's say an infinite number of other universes all within a multiverse. And let's say that the...

Homework Statement The half life period of N-13 is 10.1 minute. Its life time is ------- The answer has been given as infinity. Could someone help the formula to arrive at this answer 2. The time taken by the radio active element to reduce 1/e times is ----- The answer has been given as...

1. Suppose that two electronic components in the guidance system for a missile operate independently and that each has a length of life governed by the exponential distribution with mean 1 (with measurements in hundreds of hours). (a) Find the probability density function for the average length...

Let's say that, billions of years into the future, as the universe is beginning to burn out (by spreading itself too thin), humans decide to change the fate. Would it be possible to, say, build millions or billions of machines to go around collecting all the matter in the universe? They could...

Extending Newton's Law to real life. No more "ideal systems"! Homework Statement Newton's Laws in reality, applying all forces 10 pts? A block of mass m is hung on a pulley that is at the end of a table. The pulley connects the hanging block m and another block M that is on the table. The...

A plant for example absorbs minerals and moisture from the soil and radiation from the sun. There is a huge variety of ways that these components can be arranged, but the plant organizes them into very specific structures such as proteins, cells, leaves, stem, roots, etc. There are far more...

I am a sophomore in high-school and have been teaching myself calculus. I understand it all, but I have a hard time seeing where integrals apply to physics and real life. I get the basic stuff, like using integrals to find area on a graph, and how you can use them when talking about velocity and...

HS student taking calc 2 at community college. Currently I will have 2 exams left, and by the way things are going I will probably have a B. My mother has this sick obsessions that I must have a 4.0 GPA in order to get a future scholarship and acceptance at university. She made me re-take...

I am meant to deduce the half life from this table (as attached.) I was under the impression that the half life would occur when the initial activity was halved but my answer of 2.34 minutes (from halving the initial activity of 36506) is wrong. Instead, the answer the textbook got was 1 minute...

Hello, I am interested to know how many readers think that we will find life in our solar system, if so when?. I am confident that we will find basic life forms in a human lifetime. also if anyone thinks that there is more that one intelligent civilisation in our galaxy other than our own...

For example, I just heard that ATMs are possible thanks to the development of elliptic curve theory. Also that internal cell phone antennas are an application of fractal theory. Can you share any other specific examples?

For the past year or so I have been really torn between choosing engineering, physics, or a combination of both. To note, I am a freshmen in college but I need to start forming an idea now because the science and engineering field is really vast. I have a huge passion for understanding the...

I must derive the 1/4th life expression for a first order rxn. ln(\frac{[A]_{\circ}}{[A]_{t}})=kt ln(\frac{[A]\circ}{\frac{1}{4}[A]_{\circ}})=kt_\frac{1}{4} ln(4)=kt_{\frac{1}{4}} do I set t=1/4 ? \frac{ln(4)*4}{k} \frac{5.545}{k} What am I doing wrong here? The answer is allegedly...