Life Definition and 1000 Threads

Here's the short version: Live in New Zealand, been offered an excellent PhD position in the UK. Family won't allow me to leave. I don't want to throw away this opportunity. Long version: My biggest ambition was to get a PhD (physics) from a good university. After 5 years of hard work I've...

Homework Statement A standard light bulb is claimed to have a lifelength of 8000 hours with standard deviation of 800 hours. A newly designed light bulb is claimed to have a life length of 9200 hours with a standard deviation of 600 hours Homework Equations If 36 standard and 36 newly...

Are viruses life?

Long story short, a family member of mine is planning a party for next week and it's causing so many problems. It's going to be about 80-100 people and it's for the various graduates in our family, including meeee! Now of course, the party planning is driving everyone crazy, especially the...

I used to be really motivated because I had bad self esteem (I still do but not as bad). I used to think that I'm not good enough as a person and that motivated me to do a lot of things such as going to the gym, learning how to fix cars, surfs, building things etc. I remember working out 6...

Homework Statement A parent isotope has \tau_\frac{1}{2}=\delta. Its decays through a series of daughters to a final stable isotope. One of the daughter particles has the greatest half life of \tau_\frac{1}{2}=\alpha-- the others are less then a year. At t=0 the parent nuclei has N_0 nuclei...

What level of confidence can be assigned to the statement that all life on Earth has one point of origin - a foundation species? Also, is there any evidence that there may have been other genetic lines, other foundation species and their descendents, that did not survive. I am not asserting...

Everone is curious if there is any extra terrestrial life beyond our blue planet. do aliens really exist? Some organizations claim that they've got the strong evidences about existence of alien or the landing of alienship on earth, is it true? any comments'd be appreciated. cheers...

I'm an Australian , living in Lebanon studying . I as a grade 11 student , Infact, the schools semister is almost finished. So what I'm trying to say that I should pick the domain I have to go through. I do well in math and physics my grades are high , I'm looking forward to be an engineer...

Homework Statement A sample of radioactive nuclei of a certain element can decay only by gamma -emission and beta -emission. If the half-life for gamma -emission is 24 minutes and that for beta -emission is 36 minutes, what's the half-life for the sample? 2. The attempt at a solution...

My "Quarter Life Crisis" :( I have no idea what I want to do. As a kid I attended several summer gifted programs for physics/math/astronomy (believe it or not), and I always thought I knew exactly what I wanted to do: study astrophysics. But I also liked studying everything else. And I do mean...

Homework Statement Ok so I'm doing this practise problem but I have no clue what to do. "A radioactive sample intended for irradiation of a hospital patient is prepared at a nearby lab. The sample has a half-life of 83.61 h. What should it's initial activity be if it's activity is to be...

Half Life / Alpha Decay Question -- No IDea Homework Statement A space rock contains 3.20 g of 147 62 Sm and 0.110 g of 143 60 Nd. 147 62 Sm alpha decays to 143 60 Nd with a half-life of 1.06 1011 yr. If the rock originally contained no , how old is it? Homework Equations ...

Homework Statement http://img5.imageshack.us/img5/8553/halflifei.th.jpg I need to find the half life time of a capacitor and the equation is above.. I know what C is but I don't know R.. is there a way to calculate R in this case? Homework Equations The Attempt at a Solution

Homework Statement If I have a circuit in which the capacitor is the large disk device and for each value of separation=d, calculate the half-life of exponential decay? Homework Equations The Attempt at a Solution What is the formula to do this?

=================================== Life is an ability of matter to manipulate itself. =================================== --- So what do you think? PS: originally I thought it up and wrote it here: https://www.physicsforums.com/showthread.php?t=302477&page=2

I can't feel my life! For some strange reason, I've been thinking a lot about this. Every day that passes and every thing that I do right after that I feel like I have done nothing and accomplished nothing. Its like a feeling of emptiness and this has been going on for the past few months. Its...

The Universe is a pool table, the big bang is the first strike and entropy will result in all the balls in the pocket. This version of the Universe is dictated by fate, everything could be calculated. Life occurs, and although it is more complex without awareness it is still a ball bouncing...

I have completed an experiment to measure the decay rate of an isotope, and I am trying to estimate uncertainties. The half life is 40 seconds, with decays counted over a 15 second period (with many of these 10 second periods for a total of 6 minutes of recordings) However in more detailed...

How long did it take life to form after the oceans had formed?

Is fire a lifeform? Fire moves, grows, consumes, needs oxygen, gives off waste and can "die".

I would like to get a general sense of the life course of a physicists. I'm finishing up my ugrad. studies and moving on to graduate school so I know of the physicist's life course up to this point. I was wondering what happens at graduate school and further on? Specifically: Graduate...

why does it fight so hard to continue it's existence? I'm generalizing all life as a force of it's own. It's one thing to say that life simply evolves, but in a universe of gases, rocks, and lots of space, how does the phenomena of "life" fit into the physics of everything? What is the driving...

Hi i m new here. i 'll get straight to the point. we know that a thermodynamic system always tend to proceed to a higher entropy level then how did 'living organisms' that are highly organized and thus have low entropy emerge from a chaotic system that has very high entropy (here the...

This question might rather be posted in Biology but since the information paradox is usually the subject of black hole physics I thought physicists may be better placed to answer it. The fact that information may be lost in black holes is considered a paradox, information is believed to be...

I'm interested to hear from Grad Students at these schools about anything they wish they had known when they were applying. How competitive/compassionate are the students? How is the weather? Are people happy? Is the town in complete economic distress? Do you like the whole department, or...

Real life momentum *URGENT* I need a few major examples for how momentum is used in real life. Any good examples?

Hello there helpful people (at least I hope so). I've been lurking in the shadows of these forums since I stumbled upon them a week or so ago and I have come up with a question I have been unable to find enough information for. I'm in my first year of a BSc in physics, although its pretty...

Can someone explain all the known paths a star can take from its birth to its death? This is what I know so far. Please correct me or add things where they need to be in the list 1) Hydrogen gas, clumps together by gravity. 2) Hydrogen atoms bump against each other and these collisions...

Homework Statement A radioactive needle contains 222 Rn (t1/2=3.83 d) in secular equilibrium with 226 Ra(t1/2=1600 a). How long does is it required for 222 Rn to decay to half of its original activity?Homework Equations A(t) = -\frac{dN(t)}{dt} = \lambda N(t) The Attempt at a Solution...

I suddenly realize that my life has no purpose. Is this how slackers feel because now I don't feel motivated to anything since it will lead me nowhere. Don't get me wrong I'm not suicidal or depressed.

Hello, I have 2 24V lead acid batteries in parallel to make a power supply for my circuit. I want to do some drain tests, and plot a curve for % energy remaining vs. time. The load on the battery isn't that large, and I don't want to have to supervise my experiment for 12 hours solid. Im...

Homework Statement Could life arise from non life today? Why? Homework Equations The Attempt at a Solution I know that it's not possible today but I'm not sure why?

Recently, I've gotten into a kind of crisis mode. I am a third year undergraduate majoring in physics. Last semester, I've overloaded myself with graduate courses and dragged through it with good marks at the end. My social life was pretty much non-existent. I slowly realized that I cannot...

Hello all, Below I have a few questions regarding calculating the half life of muons. We measured how many muons were recorded at the top of a mountain, then measured how many muons were recorded at the bottom. Using this data, we calculated the half life of moving muons. Thanks for the...

Today I went down to Albuquerque and took part in a competition called English Expo and took 2nd place in one of my two events. My friend and fellow PFer Capslockroxx was there too and got 1st in one of his events. I don't really know why I'm bothering to mention this, just felt like sharing...

Salt industry What is the industry? What chemistry is involved? Process… What products come from this process/industry? Where do the products go? Who uses them? For what do people use them? Evaluate benefits of this industry on life and society How has this production benefited...

Hi, I've been suffering of mononucleosis in late 2006. I've read that the virus never leave out the body for all the life of the infected person. I wonder if it is possible that the virus becomes active once again (like the herpes virus since they are closely related) and also if it is...

Is it just because the brain is more spongy at an early age than in our later years? I am aware that we gain new interests and knowledge as adults , but those interests are usually tied to the interests and we had as children or in our tenns / early adulthood, and therefore just continued to...

http://news.yahoo.com/s/pew/63rejectdarwinstheoryofevolution;_ylt=An8rzCf84KVpYf08mAMFUO8DW7oF After all of these years ... Perhaps what we are witnessing is the exhibition of " an evolutionary trait " deemed as common sense. Really - why do some scientist believe that there is an...

http://content.nejm.org/cgi/content/full/357/4/328

What do you guys reckon to the odds of us finding alien life? The fermi paradox: 'If there are all these billions of planets in the universe that are capable of supporting life, and millions of intelligent species out there, then how come none has visited earth?' I reckon there exists...

Hai everybody! Could there be Life on Mars ?Are there any chances that the martians could be living. Once a report was published stating that a female was seen on the Mars,is that true ? Another report came stating that Water is found in the rocks as crystallized water. Can we...

First off, i love to bodybuild, that's my life right there, but i also love learning about the orgins of space and how its made and BEYOND. BUT If i want to pursue my life into become a physicist, will i have time to work out and eat my 6 meals a day? And get an 8 hour sleep? Whats the life like...

Why do some scientists assume that intelligent life may be rare--that because only one high-intelligence--homo-sapiens (us) developed on Earth, that inteligent life is rare to evolve throughout the universe? Instead of seeing it that way, why can't you turn that thought around and assume that...

Hi. I worry far too much about life. Mostly about stupid stuff like "I'll never go down in history". That's the main one actually. It's getting to the point that I can't really concentrate on anything I enjoy. I sit and read up on mathematicians like Terence Tao, and ask myself constantly...

I hated to let this one go without a post. There is already a post in Astronomy linking to the video. https://www.physicsforums.com/showthread.php?p=2035686#post2035686...

Homework Statement A radioactive material has a half life of 1550 years. Find the time during which a given amount of this material is reduced to one forth. I am really not sure how to do this since we have not covered it in class yet. But, a formula that I have found involves find the...

Hi, I live in the northeast, well known for its heavy snowfall in the winter. Where I live, for the past few days, it has been raining heavily during the daytime and stopped at night. This has collected in various ducts and pipes meant to remove the water from the roof. At night, when the...

I used to always wondered why people in my age group were hopelessly passionate and seemed to fall into the stereotype of 'young and restless dreamers' until a few years ago. As I go on in college, I, as well as many other people my age, have to make more and more choices and seriously...