Life Definition and 1000 Threads

Signs point to life on Mars, billions of years ago, even before Earth.. Is it possible that Asteroid impacts, launched rocks to Earth from Mars, and the bacteria in these rocks evolved on Earth? If so how likely is this scenario?

I am a pilot with a problem. I love math and study it as a hobby but this problem seems to be beyond my abilities. I need to have help in actually solving it and would also like to know how you solved it please. Below is a diagram of a MD88. It has a wheelbase of 72ft 5 in and a wheeltrack...

Here is a brief detail on the planet i created. Mass .218 Earth's, density 5.62 g/cm3, radius .60 Earth's, surface gravity is .602 Earth's It has 1 moon that has 5% the mass of the main world orbiting 300,000 miles above the surface. It orbits a sun like star, same luminosity and mass every 342...

Would someone be able to help me with the question Life cycle of butterfly is egg -> caterpillar -> butterfly. Each week 5% of the eggs will hatch and 2% of the caterpillars will turn to butterflies. You start with 100 eggs and 60 caterpillars. Using calculus to obtain an equation...

Not your average car collision (very "real life") - no values supplied Homework Statement Hi, I've been given an assignment on a theoretical car collision. However, it is very "real world" (we are given information regarding the condition of each car before and after [particularly the...

What does science say?

Are there any real life applications of the rank of a matrix? It need to have a real impact which motivates students why they should learn about rank.

We know hydrogen atom is stable. Then, single proton is stable? Can we store it for a long time without decay? Do we have any related equation about particle stability?

I have been thinking about this recently, and I can't decide. On the one hand, many people bring happiness to other people and in some respect I assign value to that. But if you believe that human life has no value, then this is pointless as the people you bring joy to are worthless as well...

I don't think it’s possible, but just wanted to confirm since there are some lofty IQ's floating around the forum that would know for certain. More of a fundamental Astrobiology question. Can we determine life 'from a distance' with a spectrometer or by any other means? I believe we have...

If we speculate from a scientific perspective: - Is life the goal or merely a side effect of the universe process? - Are there more scientific reasons/arguments to assume that life is the main purpose of the process than not? (if we assume that there is a higher purpose of the process, above...

I was debating a friend and we started running numbers for the statistical accuracy of half-lives. I am a numbers guy(Accountant/Statistical Analysis), not a chemist. He is a scientist and his wife is a chemical engineer. Here is my question: If we have been studying half lives of...

I've always loved and been good at math, but I've never seen subjects that are taught in high school as very practical on their own. (If you like biology, you become a doctor; if you like English, you become an author?). Anyway, for me, if you like math, you become an engineer, so I applied to...

Homework Statement The smallest uncertainty in the frequency of emitted light when excited atoms return to ground state for molecules is estimated to be 8 MHz. Use this information to estimate the lifetime of the excited states. I would like to know if I'm thinking correct. Homework...

I have been having a discussion with a friend and I think we have reached the limit of our knowledge, so hopefully someone on here can help! Basically the question is if a photon is emitted it will travel forever providing it never hits anything. So let's say we are close to the edge of the...

This month I surprised myself in a fashion unusual for me. Having attended less than 20% of my lecture courses throughout this academic, continually abused drugs and alcohol, gotten into severe financial difficulties, and ruined my relationship with my parents, I estimated that my average mark...

Suppose we found a perfectly preserved genome of an extinct species (maybe in a amber). Would it be possible to bring back the organism to life. (I know this question resembles Jurassic Park but I'm looking for realistic answers). Like let's say a mosquito or some other blood sucking...

Homework Statement The activity of a radioactive nuclide drops 78.5% of it's initial value in 2000 years. Homework Equations I know I need to use the decay constant to work out my answer so I have re-arranged the equation as illustrated in my picture, the only problem is I cannot...

I graduated in 2008 with an EE degree and entered grad school immediately after. I excelled and did ok in my classes and research but I knew I wasn’t doing as well as I could have been doing (got a couple B minuses too). At the end of the first year I started getting paranoid that I was going...

I will try and keep this to-the-point. I'm 26 years old. I've been going to school on and off since I was about 19 while working. The years from when I was 19 until about 24 I was in exploring mode. I took a lot of generals. Neither of my parents went to college so I did not have a lot of...

or can synthetic dna give life to a dead cell. i.e when scientist removed genetic material of a cell, didn't the cell died. And when this synthetic genome is injected into the nucleus, it survive. Is this what happened.

hey, thought i would throw this problem out there... if you have the luminosity of a red supergiant 400,000 times more luminous than the sun and a mass of 30 times greater than the sun how would you go about answering how much longer or shorter than the sun would you expect it to liv...

Hey people, 1. The problem statement, I'm doing a Uni Art assignment, and I'm going to be projecting a video onto a canvas (which I don't know the exact dimensions of yet). Video file dimensions are stated as 1080 x 980 and so forth, whereas the real life canvas will be something like 50...

I am looking for some information on how to calculate fatigue life for materials at temperatures elevated into the creep realm. ASME Sec 8 Div 2 describes how to do this for carbon steel below 700F and stainless below 800F, but I am interested in temperatures > 1000F. I am performing an FEA...

Because it take about 3 generations of stars to build enough carbon to the point where life is possible, roughly 9 billion years, our Earth therefore was among one of the first planets that housed enough carbon to make life possible. Stars will continue to exist for hundreds of billions of...

I have this book with me called "THE NIGHT SKY" and on page 115 they mention Neutronium/Neutron Star material as being indestructible yet weighing A LOT to the point it will sink through the earth, so my question is, is it truly indestructible and if so why?

Hi, All: I know very little physics and/or materials engineering. I am just trying to see if there is something to the claim that alternating the usage of , say, backpacks/ shoes , will give an overall longer total life, i.e., if I will be able to get more useful days out of 2...

When you have lots and lots to learn, how do you handle it all? Do you have a specific schedule that you stick to or are you more flexible? What works best for you? When you burn out, what do you do? How do you fit in everything? (thank you)

Hi all, Don't worry, I'm not one of those wackos trying to convince you ghosts exist. I don't even believe in spirits. What I do believe is that people are really experiencing real things, but I believe that there is a scientific explanation to it all. I'm not a physics wiz, so I'm hoping to...

Hi, I'm a physicist with a layman's interest in biology. I was just wondering what the physical requirements for the origin of life on Earth are expected to be. So, for example, pressure range, temperature range, chemicals needed etc. If this has an answer, how confident is the community, or...

Power to lift* a piano A piano of mass 200 kg is lifted vertically by a 0.5 hp motor. Given that 746 watt = 1 hp, how long will it take the motor to lift the piano to an apartment that is 20 m above the ground? Not really sure how to start this question, so any explanation would be greatly...

I decided to keep a topic to talk about my life as a college dropout, starting last week, for my own introspection, as well as to yield some insights/deterrences for others. Just some background: I was an above-average physics freshman, not the best but also not the worst. I was pretty...

Homework Statement Initially, a particular sample has a total mass of 200 grams and contains 256 x 1010 radioactive nuclei. These radioactive nuclei have a half life of 1 hour. (a) After 3 hours, how many of these radioactive nuclei remain in the sample (that is, how many have not yet...

For those who don't know, HST stands for holy shonen trinity, and represents one piece, naruto, and bleach, the 3 most popular current shonen jump manga. In this battle, the HST are spread uniformly across south america, except the ships & their crews and seakings, who are on the coast around...

Hi guys, I'm interested in developing a small gps receiver that I can fit into a certain object so that when it gets stolen I can send a text to it, find the coordinates and track it. The sixe of space for the gps device to sit in would be approx ∅30mm, length is not an issue. I am not an...

I was just thinking last night about all of the things I can do now via the internet that was either impossible before or time consumming and difficult at the least. I can send and receive mail instantaneously, I can get and pay bills online. I can access books I never even knew existed...

Homework Statement The present day value of the uranium isotopic ratio U-235/U-238 is 0.00723. The half life of U-238 is 4.51 x 10^9 and the half life of U-235 is 7.13 x 10^8 years. What was the U-235/U-238 isotopic ratio 2 billion years ago when the Oklo natural reactor was active...

hey , i want to hear your opinion on good books i could read . I just read "whats life? and mind and matter by Erwin Schröndinger , and I am looking for a book that tries to answer similar questions in a physical or philosophycal way , but from a different perspective, and with some...

Hello I was wondering if someone could explain why a half life exist? What attribute of radioactive matter requires that on average half of the particle decay within this so called half life period. Why couldn't it vary? thanks

hi, I'm simulating a system of molecules (water) and in order to pass through a barrier they have to overcome an energy barrier of 4kT. What is the probability of a water molecule passing the barrier or perhaps what is the average energy of a water molecule in my system? I know it's 1/2 *kT...

http://science.nasa.gov/science-news/science-at-nasa/2012/27mar_enceladus/ March 27, 2012: There's a tiny moon orbiting beyond Saturn's rings that's full of promise, and maybe -- just maybe -- microbes. In a series of tantalizingly close flybys to the moon, named "Enceladus," NASA's Cassini...

Is the process of rotting food or any organic material directly related to the half life of its components?

Our minister of Health is trying to speed through an amendment in our law on mental health care so that it becomes law prior to the conviction of Anders Behring Breivik (his trial begins in April, and is estimated to last two months): In this amendment, people guilt of atrocious acts (specified...

Europa, one of Jupiter's large moons, is predicted to have a salty ocean beneath its icy surface. This ocean is expected to have more liquid water than the oceans of Earth have. Virtually every place on Earth that we find liquid water we find at least microbial life. Based on this it seems...

Homework Statement Consider a mechanical car jack. To change a wheel it may need to lift a load of 2000N. Suppose that one rotation of the screw raises the car by 10mm. You apply a force to the end of the lever, 0.5m long, through a full circle. The jack is only 40% efficient. Calculate the...

Dear Experts There are solar charging devices in the market for electronic devices. These contain some electronics which I suppose is to regulate the power or as controller. Lets say I have a 6 volts device and I have a solar panel rated at 6v. If without any electronic controller...

I have a keychain-type red laser pointer (5mW typical type) and I was using it for something when all of the sudden it is really dim. Even if I bump up the voltage it is still dim and I'm suspecting it is fried. I overvolted it for about 2 sec with a weak 5v source off an arduino but it worked...

Hello everyone, This is the life cyle of H.diminuta. My question is the 4th point. It says ingestion of these arthropods/fleas by rats or humans. Do rats actually eat these fleas, or do the fleas live on rats's skin and suck their blood and via that infects rats, same for humans. Is it...

Homework Statement Carbon 14 has a half-life of 5730 years, what fraction will have decayed in 2300 years? Homework Equations Nf/No =e^-kt The Attempt at a Solution Nf/No =e^-1.21 x 10^-4 x 2300 =0.068585374 However if I use Nf =No(1/2)^2300/5730 I get 0.757125224 I...

Quantum Man: Richard Feynman's life in science I registered, perhaps after it is over we could discuss in this thread. Rhody...