4 ms·
Astronomers agree: Universe is nearly 14B years old
- allears 6y agoThe interesting question is what was happening 15 billion years ago.
- hcarvalhoalves 6y agoI'm not a physicist, but I believe the current understanding is that there's no 15 billion years ago. Time is a side-effect of measuring entropy, and according to the Big Bang theory you go backwards in spacetime to a point of infinite density and temperature, and there's no "past" that.
- effie 6y agoTime is most definitely not a side effect of measuring entropy. Time elapsed is defined by number of periods of some (natural or artificial) periodic phenomenon. Orbiting of the Sun, or pendulum swinging, or clock hands motion, or electric circuit current oscillations. None of these periodic processes have anything to do with the concept of entropy.
- kazinator 6y ago15B years ago, the requirements started to be gathered. Coding started 14.5B years ago.
- karmakaze 6y agoThat's like asking "what's south of the south pole?"
- brokenwallet 6y agoAre you saying that we require an insight similar to thinking beyond Earth-centrism?
- effie 6y agoIf extended with given quantity "how far from the south pole", that question actually has definite answer for any observer not on any of the two poles. The only observer for whom there is no answer is the one on the south or the north pole. Regarding the time question, are we on Earth in 2021 on the poles of the time sphere, or somewhere in between them?
- karmakaze 6y agoIt requires a reformulation of the geometric question. Which is like the question of time. With our current definition/understanding relating to changes and entropy there is no 'further south' so we need to talk about something different to talk further.
- samizdis 6y agoPaper cited in article [1]: The Atacama Cosmology Telescope: a measurement of the Cosmic Microwave Background power spectra at 98 and 150 GHz - Journal of Cosmology and Astroparticle Physics [1] https://iopscience.iop.org/article/10.1088/1475-7516/2020/12/045 https://iopscience.iop.org/article/10.1088/1475-7516/2020/12...
- effie 6y agoCan someone explain what does this claim "x is y years old" even mean? Isn't time coordinate (of creation of x) dependent on the reference frame of the observer? Which frame is used here?