Life Definition and 1000 Threads

Hello, I'm new here, and I really don't know much about astrophysics so would appreciate it if your replies were as simple as possible I've read that scientists are hopeful to find life on Titan, Saturn's largest moon, because the planet resembles Earth in its earlier stages. I have a few...

I am watching this now and it looks pretty interesting. One thing that caught my attention was a segment about a Japanese school that teaches internet etiquette to young children. http://www.pbs.org/wgbh/pages/frontline/digitalnation/etc/synopsis.html Watch online...

Hi, A few days ago I attended an astronomy lecture and while explaining the basic theoretical background of astronomy the lecturer compared the expansion of the universe from the big bang onwards to a balloon filling with air. Since the galaxies/stars are (loosely speaking) dots fixed on...

Hi guys i'm having much difficulties in understanding the relations between half life, decay constant and activity. I'll explain what i known here. T^{\frac{1}{2}} is the half life which is the time to reduce the nuclides by half. \lambda is the decay constant which can be solved...

I'm skeptical of "proof" of past life on Mars as as result of rocks found on Earth. I'm skeptical of "proof" of past life on Mars as a result of rocks found on Earth. http://www.digitaljournal.com/article/285660" Wouldn't real proof be found on the planet? I thought these Martian...

I'm guessing this is the right forum to post in. Ammonia shares many properties with water. It is polar, it is amphoteric, it reacts with itself to form its acid and base conjugates NH4+ and NH2-. Just as water is our basis of life, could another species use ammonia like we use water...

Homework Statement Calculate the half life for alpha decay of ^{208}_{82}Pb (in years) Homework Equations gamow factor transmission probability coloumb potential The Attempt at a Solution...

I love Physics and Math and really want to become good a it. I like to make exercise, hang out with friends, have a girlfriend and maybe in the future have a family. I know that you have to put the effort to succeed but i like to know if at least let you time to do the thing i mentioned above.

I have a first generation Apple iTouch 16 GB, and frequently download podcasts to watch and listen to. With over 1 million applications written, I have searched in vain to locate an application that will allow you to launch a video, and instead of displaying video and audio to suppress the...

can anybody tell me what the life of a aerospace engineer is like

I've gone through both "ZapperZ's "So you want to be a Physicist?"" and "The Should-I-Become-An-Engineer? Thread", and I am still having a tough time figuring out what exactly I want to do. Both threads, and many other threads, have given me a lot of insight about what each field involves, but a...

Just a quick thought... Everything to our knowledge is governed by four fundamental forces: the gravitational, electromagnetic, and strong and weak nuclear forces. But I am wondering, my desire to spontaneously move my hand to the right for example -- what is the explanation for this. Can...

I never had friend in my life ! I need physics friends and cool science friends. Hi, this is me kiran Do you want to know how I look like ? here is my vdo. NASA selected my vdo https://www.youtube.com/watch?v=<object width="560" height="340"><param name="movie"...

im 21 years old and i have done absolutely nothing in my life. i haven't taken the sat,act, or any type of college entrance exams. i am stuck in a rut and i don't see a way to get my life moving. i have made so many mistakes in my life. there are so many regrets i have. i remember not...

An undergrad here, about to finish up within a couple of months. My grades aren't too good overall and I think I've learned that the academic life is not for me. Well, to be more precise, the stress and pressure associated with academic life is not for me. I am thinking about the possibility of...

Hi, first of all, i am no physicist, but after doing some research on some physics theories i came to this question. If an infamous "law of everything" was discovered, and supposing we knew the state of the universe at a moment in time after the big bang, and also supposing that we had super...

1. Half life of a radioactive substance is 13 days. How long for 400 grams to decay to 300 grams? Solve algebraically and show all work. Give both exact answers and the answer rounded to 4 decimal places. So I manipulated (1/2)A0=A0e13K to obtain K = ln(1/2)/13 Where do I go from here?

Ok I'm currently exploring other forms of life, mainly silicone and ammonia based life I found out they can replace carbon and water in our system but I'm a bit stuck on the fact if they can replace both. So we would have SI instead of C and NH3 instead H2O. I think that assimilation...

This test question is really boggling me and my math group. Any help would be appreciated. We know that AT*x=AT*b is the setup, but we're not so sure how to approach the problem most effectively. Here's the question: Use the data below to find an approximate formula for the life expectancy in...

http://www.washingtonpost.com/wp-srv/local/daily/july/25/brier1.htm

A rotating disc moves in the positive direction of the x axis. Find the equation y(X) describing the position of the instantaneous axis of rotation, if at the initial moment the axis C of the disc was located at the point O after which it moved (A) with a constant velocity v, while the disc...

Is there or was there any life on Mars in the past? Do you think so? I personally don't. I think that martian meteorite got contaminated with Earth life.

Okay, so on this last section we have been learning about friction. I'm a newby and right now we know of kinetic friction, static friction, and rolling friction. So the friction occurring when a person is walking would be kinetic right? Then when a car is braking it would be .. static? When a...

I have spent the majority of my life searching for something worth doing. I study and contemplate daily in hopes that I may be able to make informed decisions. I constantly try to determine what I value most in life; however, more and more it seems that nothing really has any value. I have...

This quote that i found in the book Super Force by Paul Davies, once read, litterally summed up all the thoughts that I have had since I could remember about how the universe works. tell me if you also think its true "An intelligence knowing, at any given instant of time, all forces acting in...

Homework Statement The half life of strontium-90 is 28.0 years. Deduce that the decay constant of strontium-90 is 7.85 * 10^(-10) s^1. Homework Equations k = ln 2 over half-life in seconds The Attempt at a Solution dunno...please help me solve this!

Homework Statement A motor is connected to a solid cylindrical drum with a diameter of 1.2 m and a mass of 51 kg. A massless rope is attached to the drum and tied at the other end to a 38 \rm kg weight, so the rope will wind onto the drum as it turns. What torque must the motor apply if the...

In the chinese art of Tai Chi, the word chi is usually translated as energy. The exercises are designed to keep our energy flowing through the body. What does physics have to say about this idea? Could life be considered a form of energy?

I wonder how marine life can withstand the enormous pressures at the bottom of the ocean without being crushed. The deepest part of the ocean, the Mariana's trench in the pacific, which is about roughly 30,000 feet deep, does have some rather strange-looking sea life inhabiting it. How do these...

Just a quick question about conceptual stuff. How is momentum lost in real life? Is it because of friction or heat? Yet that only affects kinetic energy, which means that momentum should still be conserved. So, what else is there?

I'm only at the end of the second year (out of 5) of a physics bachelor. I plan on to do a Phd although I've absolutely no idea in which area (and I know the admission will be very hard). After the Phd I'd like to do research for the rest of my life. Is that possible in the US? For example...

Homework Statement Can anyone here help me find how and where trig identities are used in real life. can you also tell me which identity(with example) and is used for what purpose and how. Homework Equations The Attempt at a Solution I found out that it is used in the field...

I was looking at a program referring to dating the life of the Earth and I`m puzzled on a bit that I`m sure must be obvious to geologists. The dating was based on the ratio of lead that was present in combination with uranium. Lead being the final element after the uranium decay. It was...

I have been solving problems from the famous book, "IE Irodov" for couple of days..It was really a terrific job for Mr.Irodov to compile such a huge set of wonderful problems which are very much inspirational. I want to know about Mr. IE Irodov.. I have tried wikipedia.org and google as...

Hi guys I am currently doing some homework for physics and I am having a little bit of difficulty understanding the topic. We are currently studying half life and radioactive decay. We completed a practical involving the rolling of X number of dice and removed all dice that rolled the number 2...

i have no hope and reASON TO CONTINUE MY LIFE. its been for years that nothinss really made me happy. I am feeling like I am breaking inside. sometimes i think of ways to kill myself. i think my exictance is just a pain and sadness for my family.:frown:

with the current trend of making things better and easier for everyone,the question comes:-are we supposed to make life any easier? ps:this thread is dedicated to all those morons who sit glued to the internet 24/7 and those who basically need to get a life. A little exercise won't hurt...

Hello, In science there are so many equilibrium concepts. Pressure, electricity ,concentration... Everything seems to be moving from high to low to reach equilibrium My questions are 1. Why does everything try to reach equilibrium? (Extremes are generally harmful and for survival of...

Homework Statement Given Y=Ae-t/(lambda) find the half life in terms of A and lambdaHomework Equations Y=Ae-t/(lambda) The Attempt at a Solution every time t is a multiple of lambda the relationship then becomes (lambda(n)=A/e^n), i can't figure out how that will relate, i also tried...

1-Half life is the time it takes for half of the nuclei in a sample of radioactive material to decay(Am I right?). Why does the first nucleas that decays,decay first and the one that decays in the end, decay in the end? What's the difference between the two nuclei or what causes this the nuclei...

Homework Statement Find the half life (in hours) of a radioactive substance that is reduced by 5% in 65 hours. Homework Equations The Attempt at a Solution So looking around I find that A=A0e^-kt but I am not really sure how to solve this without having an initial ammount.

Hello, a couple decades ago, an argument was introduced in a notable physics journal of some kind, but I cannot recall the name of this argument, or the journal. I believe it might have been associated with Cambridge, but can't remember. The argument is a logical theory as to why the...

Hi We all know that the hydrocarbons are the corner blocks of life.My question is that what makes them such different?In fact what is the difference between the hydrocarbons and other molcules that gives them such property and what is this property?(I don't know how to tell.I hope you...

I am trying to determine how long a particular battery will last for my application. These numbers are just for an example. Battery stats: 12 V 7 Ah Application 1700 W Power=Current*Voltage 1700W = Current * 12V Current=141.7A Time = 7Ah / 141.7A Time = 0.05 hours Is this...

Today I was at our bookstore grabbing my copy of Goldstein and Jackson for THAT semester of grad school and I decided to pick up some notebooks and paper too. I've come to realize that I've become very picky about paper and pencils! I look back on my undergrad work and I can barely read any of...

A thread\blog of some aerospace stuff I get to do on a day to day basis. These photos are from the AUVSI convention I went to last week. I will be attending a CFD training session\conference in early September out in California. I'll post and pictures from that if I take any, though I doubt it...

If one surveys stars, and their planetary systems, of 4.5 - 5 Byrs old; and then detects terrestrial exoplanet of say 1.5 Earth masses, then one probably still has a magnetosphere - if we are typical (Copernian Principle). And if in habitat zone, then also look for oxygen signature in...

http://news.bbc.co.uk/2/hi/8196807.stm You just can't make this kind of nuttiness up. You just can't...it's funny and sad at the same time. put it on mute, and play your favorite music in the background. They all nod to the beat!

A friend of mine says he has formulated a theory about life which suggests that a decent percentage of cells in a multi-cellular organism doesn't contribute to the organism as a whole and merely exists eating away its resources. Generally speaking, not all cells of type x supposed to do some...

I'm turning 20 in a month. I recently got accepted into UBC (college transfer) and i can't get into the 2nd year engineering program because of one course... physics 153. otherwise i have everything else. I registered this year crack of dawn and i wasn't even able to take physics 153 because of...