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How might the universe look if the second law of thermodynamics worked in reverse? Instead of the universe's entropy increasing over time, entropy would generally decrease over time in this alternate universe. Might life have still come into existence, and if so how might it be different? I heard about an MIT study about how the universe's increasing entropy might make the development of life inevitable, which got me interested in this question. How might stars, galaxies, planets etc might look if they even exist at all? 2600:4040:1014:7300:594B:5953:EE8F:274C ( talk) 00:49, 6 November 2022 (UTC)
Along a similar note, how might the universe look if it was possible to create energy out of nothing or destroy energy? 2600:4040:1014:7300:594B:5953:EE8F:274C ( talk) 01:14, 6 November 2022 (UTC)
So anything might be possible in that case (and its impossible to predict) because the laws of physics can change over time. — Preceding unsigned comment added by 2600:4040:1014:7300:594B:5953:EE8F:274C ( talk) 02:05, 6 November 2022 (UTC)
In several definitions of physical quantities, we find a multiplication by a second (J.s, A.s) when we refer to a quantity dependent on the time which flows towards the future and therefore expressed by the division of a second. Mathematically, I understand the operation, because it ultimately consists in removing any reference of this magnitude to time. In physics, the division of time on a quantity relates to associating a time interval which flows towards the future with this one (J/s, C/s, m/s), this is regularly experienced. On the other hand in physics, the multiplication of time on a quantity would consist in associating a time interval which flows towards the past, except that has never been experienced (except by reversing the progress of a video!). How can we allow ourselves to use this kind of notion in physics when it only comes under the domain of mathematics or science fiction? Malypaet ( talk) 02:49, 6 November 2022 (UTC)
I feel the OP would benefit from a course in calculus explaining the operator ρ/ρt that means the differential with respect to time of anything that varies with time, evaluated at one given instant in time. Becoming able to understand Maxwell's equations that employ differential operators to reveal the interdependence of electric and magnetic fields, and their importance in the technologies of Electromagnetism (light, radio, TV, radar) should remove any doubt that physicists "can allow themselves" to use these calculations. Of course they are aware that any practical measurement of a ρ/ρt value will require collecting values of the varying quantity during a finite time span which may be as short as measurement accuracy allows. For example: two photographs of a car showed it was at time(hh:mm:ss)/distance: 6:00:00 / 5 miles and 6:00:01 / 5-1/60 miles. The photographs are enough to convict the driver of exceeding by 10 mph the local speed limit of 50 mph but nothing is, nor can, be implied about his behavior before or after the measurement. After calculating velocity = ρ (position)/ρt for a car one may further calculate its acceleration = ρ (velocity)/ρt = ρ2 (position)/ρt2, also applicable to a given instant with no implications for the past or future. Philvoids ( talk) 16:08, 7 November 2022 (UTC)
I have two cats; each cat has eyes that reflect in a different color. One reflects red, the other green. I had assumed eye reflection color would be species dependent, but evidently it is not. What determines the color of eye reflection? 136.56.52.157 ( talk) 03:09, 6 November 2022 (UTC)
I remember reading about an animal that may or may not actually exist. It was microscopic and had only a single layer of cells in its body. It was like a sausage in shape, with a pore and extra cillia on each endd Quick Trundleteacher ( Talk) ( Inputs) 18:52, 6 November 2022 (UTC)
Why is there such a lack of variety of non avian dinosaurs in the Jiufotang formation compared to the Yixian formation which has iguanodonts, compsognathids, therizinosaurs, sauropods, ornithomimosaurs and troodontids, while the Jiufotang only has microraptorines, ceratopsians, ankylosaurs, and proceratosaurs which the Yixian also has? CuddleKing1993 ( talk) 19:44, 6 November 2022 (UTC)
Science desk | ||
---|---|---|
< November 5 | << Oct | November | Dec >> | November 7 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is a transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
How might the universe look if the second law of thermodynamics worked in reverse? Instead of the universe's entropy increasing over time, entropy would generally decrease over time in this alternate universe. Might life have still come into existence, and if so how might it be different? I heard about an MIT study about how the universe's increasing entropy might make the development of life inevitable, which got me interested in this question. How might stars, galaxies, planets etc might look if they even exist at all? 2600:4040:1014:7300:594B:5953:EE8F:274C ( talk) 00:49, 6 November 2022 (UTC)
Along a similar note, how might the universe look if it was possible to create energy out of nothing or destroy energy? 2600:4040:1014:7300:594B:5953:EE8F:274C ( talk) 01:14, 6 November 2022 (UTC)
So anything might be possible in that case (and its impossible to predict) because the laws of physics can change over time. — Preceding unsigned comment added by 2600:4040:1014:7300:594B:5953:EE8F:274C ( talk) 02:05, 6 November 2022 (UTC)
In several definitions of physical quantities, we find a multiplication by a second (J.s, A.s) when we refer to a quantity dependent on the time which flows towards the future and therefore expressed by the division of a second. Mathematically, I understand the operation, because it ultimately consists in removing any reference of this magnitude to time. In physics, the division of time on a quantity relates to associating a time interval which flows towards the future with this one (J/s, C/s, m/s), this is regularly experienced. On the other hand in physics, the multiplication of time on a quantity would consist in associating a time interval which flows towards the past, except that has never been experienced (except by reversing the progress of a video!). How can we allow ourselves to use this kind of notion in physics when it only comes under the domain of mathematics or science fiction? Malypaet ( talk) 02:49, 6 November 2022 (UTC)
I feel the OP would benefit from a course in calculus explaining the operator ρ/ρt that means the differential with respect to time of anything that varies with time, evaluated at one given instant in time. Becoming able to understand Maxwell's equations that employ differential operators to reveal the interdependence of electric and magnetic fields, and their importance in the technologies of Electromagnetism (light, radio, TV, radar) should remove any doubt that physicists "can allow themselves" to use these calculations. Of course they are aware that any practical measurement of a ρ/ρt value will require collecting values of the varying quantity during a finite time span which may be as short as measurement accuracy allows. For example: two photographs of a car showed it was at time(hh:mm:ss)/distance: 6:00:00 / 5 miles and 6:00:01 / 5-1/60 miles. The photographs are enough to convict the driver of exceeding by 10 mph the local speed limit of 50 mph but nothing is, nor can, be implied about his behavior before or after the measurement. After calculating velocity = ρ (position)/ρt for a car one may further calculate its acceleration = ρ (velocity)/ρt = ρ2 (position)/ρt2, also applicable to a given instant with no implications for the past or future. Philvoids ( talk) 16:08, 7 November 2022 (UTC)
I have two cats; each cat has eyes that reflect in a different color. One reflects red, the other green. I had assumed eye reflection color would be species dependent, but evidently it is not. What determines the color of eye reflection? 136.56.52.157 ( talk) 03:09, 6 November 2022 (UTC)
I remember reading about an animal that may or may not actually exist. It was microscopic and had only a single layer of cells in its body. It was like a sausage in shape, with a pore and extra cillia on each endd Quick Trundleteacher ( Talk) ( Inputs) 18:52, 6 November 2022 (UTC)
Why is there such a lack of variety of non avian dinosaurs in the Jiufotang formation compared to the Yixian formation which has iguanodonts, compsognathids, therizinosaurs, sauropods, ornithomimosaurs and troodontids, while the Jiufotang only has microraptorines, ceratopsians, ankylosaurs, and proceratosaurs which the Yixian also has? CuddleKing1993 ( talk) 19:44, 6 November 2022 (UTC)