What is Death: Definition and 333 Discussions

Death is the permanent, irreversible cessation of all biological functions that sustain a living organism. Brain death is sometimes used as a legal definition of death. The remains of a previously living organism normally begin to decompose shortly after death. Death is an inevitable, universal process that eventually occurs in all living organisms.
Death is generally applied to whole organisms; the similar process seen in individual components of a living organism, such as cells or tissues, is necrosis. Something that is not considered a living organism, such as a virus, can be physically destroyed but is not said to die.
As of the early 21st century, over 150,000 humans die each day.Many cultures and religions have the idea of an afterlife, and also may hold the idea of judgement of good and bad deeds in one's life (Heaven, Hell, Karma).

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  1. Eagle9

    What toxins do the E.coli bacteria generate at death phase?

    I have heard that bacteria produce some chemicals/toxins when it dies at the death phase. I need to know exactly what chemicals are produced by E.coli when it dies? Ethanol? Peptides? It this problem explored? If so – how these toxins impact on bacteria? :rolleyes:
  2. G

    Weakness of Death Star: A Space Opera Scenario

    I think about a space opera, and a Death Star like scenario in it. I intend to make it harder than SW. I had the following idea : they hollowed out a big metallic asteroid, spinned it up, kept a large portion of the outer layer as armor, and built a fusion reactor in the middle of it. They want...
  3. Emmanuel_Euler

    What Happens if a Black Hole Dies or Disappears?

    what does happen if the black hole died Or disappeared??
  4. JohnPrior3

    Death of Sun: Habitable Zone & Timeline

    So I am working on making a simulation that shows the habitable zone of our solar system from now until our sun reaches the end of it's red giant phase. The sun will die when it is 10 billion years old and will reach the end of the red giant stage at 5 billion years. I know the habitable zone...
  5. C

    Did Stephen Hawking Believe in an Afterlife?

    I came across this article: http://www.theguardian.com/science/2011/may/15/stephen-hawking-interview-there-is-no-heaven In this article he states that heaven "is a fairy story for people afraid of the dark", but I don't get the point, when Hawking says there is no being after death, then there...
  6. H

    When did the zombie apocalypse begin?

    http://deathdate.info/s/death my death date according to this site is January 22 2054
  7. W

    Death Ray New Approach - Is It Possible?

    When people attempt to build one, they usually put objects near its focal point in front of the mirror but i wonder, has anybody tried "collecting" the light and aligning the beams in some way to be used as one? I know that the light is coming under different angles but is it possible to align...
  8. E

    Why do people get very cold shortly before death?

    Why do terminally ill people become very cold hours before death?
  9. O

    Death Spiral of electrons into the nucleus

    So electrons were suppose to crash on nucleus according to classical physics. I want to understand the dynamics of it. The basic idea is that it will slow down as it emit photons. But with what force and mechanism? I think the answer is related with Abraham-Lorentz force, but i see too many...
  10. G

    Does anyone NOT believe heat death is the final destination?

    And if not, what do you believe?
  11. avito009

    What prevents a star from collapsing after stellar death?

    When the star stops burning because heavier elements like Iron are formed in its core. Then the gas pressure stops and as you know the gas pressure helps keep a star in equilibrium because it provides pressure against the force of gravity. So Iron does not give off energy. So what stops the star...
  12. K

    Does discrete logic equation ignore death rate during off season?

    Observation of the growth of some beetle population suggests that discrete logistic equation would be more appropriate since these animals have distinct breeding season. discrete logistic equation: Xn+1=Xn+rXn(1-(X2/K)) the result of this equation accounts for population only season to...
  13. S

    Karma: Is There Scientific Proof? Exploring Morality & Life After Death

    You folks are the geniuses I have ever seen. So please tell me,is there any scientific proof for Karma?(I ain't asking any explanation from religious point of view). In some part of our life we might have done something immoral to others. In the same way,we may also get harmed by others. So if...
  14. P

    Solve the Murder: Uncovering Time Since Death with Equations

    1 the problem and all known variables. A person is murdered in a room with a temperature of 20 deg C. At the time the body is discovered, the body temp is 32 deg C and is decreasing at an instantaneous rate of .1 deg C/minute. How long ago was the murder commited? 2. Related equations...
  15. K

    Is tesla death ray ( death beam ) exist ?

    i wonder about tesla death ray. is this machine really exist ? or just conspiracy theory ?
  16. G

    Relative death of people traveling at the speed of light

    Hello. So I always hear people say, "If someone flew in a ship at light speed to a far away star and then came back to earth, and it only took him two years to travel (the star being a light year away). When he came back all of his family/friends would have been dead for a long time." My...
  17. julcab12

    Death and Resurrection of the Zero-th Principle of Thermo

    ..Quick rundown on 0-th principle of thermodynamics in relation to GR and QM. Some insight on LQC-(slide to 19:07) using quantum state 'of' time in a semi-classical approximation. Fun way to think of things.^^
  18. J

    The KKK tried to build a death ray

    I know it's old-ish news, but I just heard about it in an engineering class recently while we were talking about ethics. Apparently two guys, one a member of the KKK, decided that they would try to hack some medical equipment into a serviceable X-ray "cannon" that would expose those they deemed...
  19. S

    Difference between Heat Death and the Big Freeze ?

    Difference between Heat Death and the "Big Freeze"? I'm a little confused. My understanding of the two is that once energy has been distributed evenly all through the universe from reactions and processes occurring, then there will be no more space for more energy to be distributed, and no more...
  20. C

    Light Speed: Exploring the Possibilities of e=mc2

    Howdy, This is my first post. Please be gentle. ;-) I have been thinking about the speed of light. Scenario 1: I'm on a train traveling at the speed of light. Everything in the train immediately about me appears normal. The reflection in the windows, looking down at myself, indeed...
  21. C

    Birth and death rates of roaches.

    Homework Statement Consider a population model in which the birth and death rates and  of a cockroach population P are both proportional to sqrt(P). (Recall that in a “normal” exponential growth model, B and  D are constants.) If the cockroach population has increased from 100 to 400...
  22. K

    Quantum heat death already occured?

    To experts in Bell's Theorem and Non-locality.. like DrChinese... what do you think of this. is there a way to refute it? http://blogs.scientificamerican.com/critical-opalescence/2013/11/18/cosmological-data-hint-at-a-level-of-physics-underlying-quantum-mechanics-guest-post/ Someone said...
  23. F

    Grad School: Is a disciplinary sanction for drinking a kiss of death?

    Hello wise physicists, I didn't know who else to ask this question to - so I am posing it to other physics students and people who have been through the program, maybe even with a dilemma similar to mine. I'm new here to the forums. Currently a 4th year Physics major at a top 10 undergrad...
  24. aleemudasir

    Death of an Organism: Event or Series of Events?

    Is death an event or a series of events?
  25. Student100

    Does time perception change in near death patients?

    Hey, I was wondering if anyone had read any studies into time perception before or near death, I tried googling it and get the anecdotal "my life flashed before my eyes" type deal. I'm actually more interested in studies and published works though. I was curious about the subject and would...
  26. phinds

    News Is Ted Cruz's Comparison to the Bataan Death March Appropriate?

    Ted Cruz, in his marathon blather on the Senate floor, included ... well, here's a quote from a news source reporting his thanking the people who had put up with him: I find this deeply offensive to the memory of those who actually were ON the Bataan Death March. Does anyone here find this...
  27. D

    Discrete Time Birth and Death Process

    Homework Statement Consider a discrete time birth and death process in which the maximal population size is N = 6. Birth rates and death rates are directly proportional to the current size Xt of the population at time t (t = 0; 1; 2; : : :). If the maximal population size is reached, no more...
  28. Nugso

    Heat Death of the Universe: Is It Inevitable?

    Hello. I a few hours ago opened a new thread called "Big Crunch". But now that I've learn that it's not really possible for Big Crunch to happen, I also look for another possibilities. It looks like the best theory is Heat Death. It says that all stars will be dead the temperature will be the...
  29. M

    Entropy of a vacuum and heat death of the universe

    According to the third law of thermodynamics, one could argue that a vacuum has zero entropy, since it has only one ground state and a temperature at absolute zero. However, assuming the accelerated expansion of the universe to result in a 'heat death', i.e. a state of absolute thermal...
  30. K

    Uncovering Tycho Brahe's Death: A Mystery Unsolved?

    My professor has been driving the class nuts by not telling us how Tycho Brahe really died. I'm having trouble with the internet because the sites I have looked at tell me exactly what my teacher tells us there is more to. Does anyone have a good link or the story of how Tycho really died...
  31. T

    School bus crash resulting in death

    My sister was recently killed in a car crash, she was the driver of the vehicle, making a left turn at an intersection heading north and was stuck by a school bus that was heading east towards her. The police report claims the driver was driving at a speed of 45 miles an hour at point of impact...
  32. S

    What is the Minimum Speed Needed for a Motorcyclist in the Globe of Death?

    1. A motorcyclist in the Globe of Death, pictured at the start of the chapter, rides in a 2.2-m-radius vertical loop. To keep control of the bike, the rider wants the normal force on his tires at the top of the loop to equal or exceed his and the bike's combined weight. What is the minimum...
  33. chaszz

    What hath Newton wrought in the two centuries after his death?

    I know that Newton's work made possible the Industrial Revolution, but I don't know how. I understand his impact on subjects like astronomy, gravity, and predicting motion, but not on mechanics and industrial technology. The steam engine was the most important machine in the early Industrial...
  34. Evo

    Nightmare bacteria causing death in hospitals

    It sounds like if hospitals take necessary precautions, deaths from the new resistant strains of bacteria can be reduced and even stopped. I am posting this so that more people will be aware of the risks and can ask about it if they need to stay at the hospital. I know I will if I have to have...
  35. J

    Circular Motion and Static Friction Problem The Wall of Death ride

    Circular Motion and Static Friction Problem.. "The Wall of Death" ride Homework Statement A fairground ride called "The Wall of Death" consists of a cylindrical container of internal diameter 6.50m, mounted on a cylindrical axis. The passengers feel as if they are being pushed against the...
  36. M

    Birth Death Model: M/M/C Queueing System

    Homework Statement So for M/M/C queueing systems, I have two types of problems that I have been asked to deal with. For the first question I am given in my notes, is where the arrival rate is constant λ=10 and service rate is μ=5.122 with 2 servers, i.e. C=2. For this question, I have used...
  37. K

    Medical Is AIDS really a death sentence?

    Is HIV/AIDS really a death sentence? I mean a 100% guaranteed fatality rate? Basketball player Magic Johnson has been living with the disease for over 25 years. Is it at least theoretically possible to survive this disease with rigorous treatment?
  38. S

    Can death be triggred by genes

    is genes responsible for natural death in animals and human beings due to aging. can aging process be reversed by controlling biological clock
  39. G

    Mechanical engineering Swing of Death

    Hi there, again maybe stupid question but I have no idea about this exercise. or maybe a little clue. i know that v=r? but with the given 40° when i convert it to a rmp it is very small value 0.111111 and the r is 3m or 7m.. Please if someone can help me.. also if someone can help me with...
  40. MathematicalPhysicist

    The Fate of the Universe: Expansion, Matter Decay, and the Ultimate End

    I don't quite understand this. Some models say that if the universe keeps expanding indefinitely eventually matter will disolve into radiation, I also read that the particles of matter such as protons wil decay (I am not sure how reliable is this if no one ever deteceted proton decaying). Now...
  41. A

    Temperature of the Heat Death of the Universe?

    Is there a way to calculate the temperature of the heat death of the universe based on the total amount of energy currently in the universe. And if the total amount of energy in the universe is zero (compose dof equal and opposite parts) is it possible for the parts to cancel each other out and...
  42. zoobyshoe

    Reexamining The Death of Alan Turing

    Alan Turing, of Turing Test fame, would be 100 today. (Google has a clever animation to celebrate.) In conjunction with that anniversary, this story was posted which questions the usual story of his death: http://www.bbc.co.uk/news/science-environment-18561092
  43. E

    How Fast Must a Car Drive to Avoid Slipping on the Wall of Death?

    Homework Statement I guess wall of death mechanic is not easy. Moving to the question. We have a mass of 1000 kg driving on the wall of death with radius 20 m. TO avoid slipping down the wall, the friction between the tyres.. Asuming that the mass is something like a car for example. Anyway...
  44. B

    Writer looking for help regarding death prediction

    Hi, I'm writing a novel set in the future and wanted to find an opinion on the future possibility of determining a person's life expectancy down to a fairly specific prediction. For example, If you had a very old man and access to all of his medical information (dna, etc.), could you predict...
  45. Borek

    News Death camps in Poland - Obama's slip

    Sigh. Who writes Obama's speeches? For many years we fought US press and media so that they will stop mentioning "Polish death camps" instead of "death camps located in Poland". Small difference in wording, but huge difference in meaning. To some extent we were successful, many important papers...
  46. zoobyshoe

    Medical Coffee Decreases Risk of Death

    http://www.npr.org/blogs/thesalt/2012/05/16/152835058/can-coffee-help-you-live-longer-we-really-want-to-know
  47. D

    Gravity speed (I know it's been beat to death, apologies in advance)

    I know the general premise is that the "speed of gravity" is equal to that of light speed, but something that doesn't quite make sense to me is this; Space itself can, and does expand faster than the speed of light right? By proxy it should be able to contract faster than the speed of...
  48. G

    Death and conservation of information

    Hi, it's quite long time I didn't post so let me start by saying that I'm not religious, not even a deist. Let me also say that I'm just a layman intersted in science without any real knowledge of theoretical physics. I'm putting this question from a purely scientific standpoint, without any...
  49. J

    Newton's Law of Cooling (Calculating Time of Death)

    Homework Statement The problem states that you discovered the body at 1pm Thursday in a freezer where the temperature was 10F. Temperature of the corpse at discovery was 40F. I have to find how many hours ago the victim died. Homework Equations You are given the formula T = Ta + (98.6 -...
  50. P

    Energy contained within Humans and what happens to it after death?

    I'm always trying to understand how things work. I find it hard to accept things that lack fact, proof, and reasoning. After losing my 21 month old son on Feb. 8th, 2012 to SPNET Brain Cancer I am trying to make peace with the situation on terms I can accept, and that means trying to...
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