Age Definition and 590 Threads

I am writing this e-mail from Germany. I came to Germany to do a PhD in sociology. I hold a bachelor and master degree in economics in my country. Actually I didn't choose my bachelor field intentionally. My inability as a teenager at the age of 16-17 to discover my abilities and fields of...

Homework Statement There are 100 employees in an organization across five departments. The following table gives the department-wise distribution of average age, average basic pay and allowances. The gross pay of an employee is the sum of his/her basic pay and allowances. There are limited...

I was thinking about the age of the universe which is said to be 13.8 billion years approximately. I read that this is derived from two sources , calculating the life of the oldest stars in the observable universe and from extrapolating backwards the distance which is radius from Earth to all...

The universe is believed to be 13.8 billion years old and at least 45 billion light-years in radius. Now there is also a black hole at the center of our galaxy, with my basic understanding of black holes I understand that this would warp time and space, is it possible that it's warped so much...

Hello. This is my first post here. I have a question about the age of the universe that has been on my mind for the last few weeks. I have just read the posting guidelines and wish to state before I begin that I do not intend this as a challenge to mainstream theory but as an attempt to...

In your opinion, how old is too old to consider a four-year math degree? Can a person who is middle age return to college to major in math even if the degree itself will not lead to a rewarding career?

I am 18, I am going to be studying German in Germany for 10 months, and then go to a preparatory year (German studienkolleg) I will probably be 20 or 21 before I start actually studying in the university ( although I finished high school at 17 and got accepted in my home country's university...

Hello, When we assume the universe is expanding at a constant rate, we could say the age of the universe is 1/Ho. but I always feel unsure about that because 1/Ho is the distance over the velocity. However, the velocity changes over time, that is, when something is closer to us, the move slower...

At the big bang, 'we' (an inside observer) were traveling at great speeds. Does this mean to say that time was 'slower' and thus the value (distance traveled in time) of time within 1 second, experienced by an inside observer, was much larger than our modern, perceived, value of 1 second? If so...

Hi, I have read that the Earth has undergone five ice ages, the latest one is the Quaternary glaciations. I know that in the ice age there are glacial periods and interglacial periods, and we are currently in an interglacial, I want to make sense what is the effect of those succsessive periods...

Hello Everyone, This is my first post, and I don't have any formal background in cosmology. I'm in the middle of reading a book called 'The Exploration of Outer Space' by Sir Bernard Lovell and I find myself falling in love with this topic! I have a question that has gnawed at my head for a...

Pleaes read the following. It its the material for a whole chapter in furture hisotry books or even whole books. It one ups Gov. Rick Scott of Florida who band the use of the terms "climate change" and "global warming" from all official communications back in 2011...

Homework Statement Currently, the density of matter ##\rho_0^M## and of radiation ##\rho_0^R## have values of approximately ##10^{-29}## g/cm^3 and ##10^{-33}## g/cm^3 respectively. Estimate the ratio of the cosmic scale factors ##a_{eq}## (scale factor at equality) and ##a_0## (scale factor...

https://www.yahoo.com/finance/video/why-working-age-men-disappeared-194401189.html What's going on with this? Is it not wanting to work or not wanting to work for low wages...or something else?

In the beginning of the universe, the hot matter of the entire universe was confined to a small volume. I would guess that compared to our time frame, time flowed slower than it does now. I would also guess that time has gradually slowed down since then. Is this significant in predicting the...

theoretically if you were in the center of the earth, would you age slower or faster from time dilation? this question is asked here as well: https://www.quora.com/Can-someone-calculate-the-time-dilation-if-you-were-in-a-5000-km-deep-cave-How-much-longer-would-my-life-be this is a wrong...

Hi everyone. I wanted to post this interesting essay by Donald and Stuart Geman on Science in the Age of Selfies. http://www.stat.berkeley.edu/~aldous/Blog/PNAS-2016-Geman.pdf The essay raises some interesting questions on the scientific enterprise in the age of online communication and great...

I'm nearly fourty; not a time when most people start I have always loved physics and math but gave up in high school when teachers always complained I ask too many questions. I always want to know the how's and why's. Questions I asked thoughts I had were called stupid but now are actually main...

How can the universe be infinite and yet have a finite age?

Homework Statement The identical twins Speedo and Goslo join a migration from the Earth to Planet X, 19.0 ly away in a reference frame in which both planets are at rest. The twins, of the same age, depart at the same moment on different spacecraft . Speedo's spacecraft travels steadily at...

Homework Statement About a day after the Chernobyl disaster the radioactive fallout landed in Sweden. The relative activity of ##^{133}I (t_{1/2} = 20.8h )## and ##^{131}I (t_{1/2} = 8.02 d)## were measured at 28/4 17:00 at ##270## mBq and ##1000## mBq respectively. Determine the time of the...

Hi, I am a 27 year old Physics Masters student and I have completed one year of my Masters degree in theoretical high-energy/cosmology from one of the top universities in Canada. I would like to apply for PhD admission to the top 20 universities in the US for a phd in theoretical...

HiIn a few months I will be celebrating my 23rd birthday. I have planned to go to college this year but it seems that I will have to postpone that till next year. By the time I will be enrolled in an electrical engineering B.S program here in Germany, I will be roughly 24 years old. The degree...

I have been to several job interviews nearly all of them have rejected me because i am 65, i have told them that i have at least another 5 years left in me but that does not wash. I have plenty of skills, electrical, pnumatics, mechanics but even with thees skills i can not get a job, do you...

In a recent thread I incorrectly stated that an observer moving at a high velocity relative to a co-moving observer would measure the age of the universe as more than the co-moving observer would. Apparently that is incorrect, and the age of the universe measured by the first observer would be...

I am assuming scientists say that the universe is 13.8 billion years old with respect to time on earth. If so, how come the infinite energy present at such a small scale didn't make gravitational time dilation infinite during the first stage? Wouldn't time dilation make the universe infinitely...

How can the age of the universe be determined when there is no absolute measure of time or distance in the universe. Every other place in the universe has another rate of the passing of time. Since time expands with the expansion of space, trying to use expanded time to measure time is circular...

If you are offered a "cure" for dying of old age, how much would you pay for it? It is not a cure against all causes of death - accidents, acute diseases, etc. can cause death. Additionally, suicide could still work. Aging continues, but it is much slower and asymptotic to infinity. Would you...

Homework Statement calculate for men and women each, the probability at which... the lifespan left, of a forty-year-old is 20-40 years. Homework Equations 3. The Attempt at a Solution [/B] That's a mouthful of a sentence. It looks like if the lifespan is exactly 20 years... there could be...

Homework Statement son and father and granpa have same value for their birthday (except the year ostensibly) father is nine times the son's age now. calculate the granpa's age now. clues - five years ago, grandpa was 32 years older than what the father was at five years ago. -in five years...

Homework Statement Homework EquationsThe Attempt at a Solution the solution according to blog is Neither May nor June is possible because they have unique dates - that means Albert couldn't know for sure that Bernard doesn't know. If Albert had May for example, Bernard might have the number...

After looking at the "doppler effect" explanation of the twin paradox, I'm under the impression that the difference in the age of the two twins has to do with the part of the diagram where one of the twins is accelerating. But, my question is, what about the "coasting" part of the diagram? So...

On Kepler B#, humanoids have survived every mass extinction as a species for millions of years. On Kepler Bb humanoids haven't been there as long. Only tens of years instead of millions. In my story about Kepler Bb I have Robin and Lisa in a stone age type civilization when they are young...

Hi everyone. I'm trying to derive the formula for the characteristic age of a pulsar. What I'm starting with is the following differential equation. dP/dt=K*P2-n What i think is odd, is several places they say solving this differential equation gives the following solution...

Here's the story. I have a composition notebook that I used to write some of my math proofs in that I want to keep. In my home, the wall of the window grew a lot of mold over the winter in areas that we were unaware of. The notebook was very close to this wall (as some other things were)...

ND Tyson tweeted that Scott Kelley aged 1/100th of a second less than his twin, Mark, while spending nearly a year in space. Isn't this a playing-out of a real "twin paradox" experiment? It seems that we have two identical twins, one of which goes on a (kind of) long space flight while the...

Does knowing the age of the universe (13.8 billion? ) say anything about size of the universe (besides the observable size)?

Hello everybody, I'm new here and this is my first thread. Just wanted some feedback on my situation. I want to go back to school because I feel I have peaked out and I'm not pushing myself to see my full potential. I have always loved math and science. I want to go back for engineering and I...

Hello, I urgently need advice on what options are best for a future career in (i) science (ii) a job unrelated to science. What options will open more doors into employment + offer more university degree courses Combination of options are: 1. Physics + food technology (cookery) + design...

Homework Statement I'm using python to calculate the age of the universe, by working out the distmodulus for a set of galaxys (using the V and I bands) then working out the distance in parsecs and then hubbles constant etc... I keep getting values that are 10s of magnitudes out which I assume...

I've never understood this: we measure the edge of the observable universe to be around 13 billion LY away, so we are seeing the state of things 13 billion years ago. But 13 billion years ago, wasn't the universe much, much smaller? Did distant quasars and galaxies look like they do "now" so...

OK I might be stupid and english isn't my native language, so I'm sorry in advance. So: The red shift is bigger, the further away a galaxy is (they move away faster), and the closer it is, the shift is smaller and it goes to blue for Andromeda (towards). Everyone knows that. BUT When you...

I saw a $75 textbook on Amazon that I wanted. But every book I've bought from Amazon has been so badly made that I consider this a last resort. While wondering what to do, I came across this. "First a rant: What has happened to the once high art of bookbinding? I have hardcover books, with...

I have on several occasions on PF flagged up examples where it appears that there is an age problem in the early universe, in other words highly evolved objects have been observed whose existences are difficult to explain at their high red shifts in the standard \LambdaCDM cosmological model...

Homework Statement The half life of U-238 is approximately 4.4 billion years, while U-235 is approximately 700,000,000. A Uranium ore has 0.75% U-235. Assuming there was an even amount of both types of Uranium when the Earth was formed, estimate the age of the Earth. Homework Equations N =...

I'm trying to reconcile the age and size of the universe. The size of the universe is more than twice the distance light can travel in the time it has existed. Does this mean that the universe is expanding faster than the speed of light or that it did initially and has slowed down since? I...

Hey Friends, In Einstein's special relativity I find "Twin Paradox", where Dick and Jack, two twins . one of them went to space at a speed of 0.80c to a star 20 light year away (where c is the speed of light) and other remains on earth. When Jane returned to Earth his age was...

This paper: http://arxiv.org/abs/1509.02832, The Age Distribution of Potential Intelligent Life in the Milky Way, estimates the age distribution of intelligent civilazations in the Milky Way. Unsurprisingly we rank somewhat below the advancement level of termites compared to your typical ET. It...

Hello, I've a problem. I need to find the age of universe in normalized Planck units. In my case, I'm using Planck mass = 1 and: ##H = 1.18 × 10^{-61} \times t_P^{- 1}## With these values, how can I find the age of the universe? Thanks!

The problem The isotope ## ^{14}C ## has a half-life of ##5730## years. The ratio between the amount of ## ^{14}C ## nuclei and ## ^{12}C ## nuclei in a living matter is ## 1.3 \cdot 10 ^{-12} ##. When an organism dies the amount of ## ^{14}C ## atoms starts dropping and thus the ratio...