Showing posts with label Planets. Show all posts
Showing posts with label Planets. Show all posts

Sunday 11 August 2019

Time one or many things?
When we think of time we think of it as just one thing, the ticking of the clock. But time has a number of properties and not all of them vary together, nor are all of the properties of time necessarily continuously present. Some properties can be at zero, null, indeterminate or absent altogether.
Let’s start with an example of a property that has actually been dropped from the concept of time, that of ‘Cyclic Time’. Jump back even a few hundred years and this would not only have been considered a natural property of time but an essential or even fundamental property. Everything in the ancient observable world is cyclic.
Indeed, ‘Simple Harmonic Motion’ is still one of the cornerstones of physics and SHM is seen throughout the physical world. SHM can not exist independently of time, but time can exist without SHM as far as we can tell.
If we can drop SHM from time simply because time can exist without it then what of the other properties that time can live without, at least under some conditions?
At the quantum scale when considering single quantum events we note that there are no components of entropy present. The test for the absence of this property is a hypothetical video of a single interaction or an animation based on the data: could we or anyone else tell if the video clip was being played forward or backward? If not then the entropy property is absent. But what of a spatial extension that contains nothing above the quantum scale? Time is still present in the form of spacetime ~ space isn’t completely flat anywhere so the bit of curvature present needs the temporal dimension to describe it. But there is no entropy. Even the virtual particle, the quantum noise, can proceed in either direction.
So there we have two examples of where entropy, and therefore the arrow of time and even the time line are not present. As with cyclic time, each of those concepts can not exist independently of time, that is, entropy can not proceed independently of time.
The interval is another example, as is change and relative time. So what property of time is essential? There must be at least one property of time present for time to be said to be present, but it doesn’t matter which one. A photon can flit across the universe without accumulating an interval of any duration at all, so change can occur without a local interval.
In our usual experience, all the properties of time, including the cyclic component, are present and so it is an effort to imagine time without even one of the properties. As we probe into the physical world, some properties can be dropped or minimised but no property is always present in all conditions, the closest would be relative time as the observer’s clock ticks on regardless of any philosophical musings and so is readily compared to all other clocks in real and hypothetical conditions.

Sunday 23 April 2017

New planet that is size of Neptune discovered:

Astronomers have discovered a `lost' planet about the size of Neptune tucked away in a solar system 3,000 light years from Earth. The new planet, Kepler-150 f, was overlooked for several years, according to researchers at the Yale University in the US.
Computer algorithms identify most such “exoplanets“, which are planets located outside our solar system. The algorithms search through data from space mission surveys, looking for the telltale transits of planets orbiting in front of distant stars.
However, sometimes the computers miss something.In this case, it was a planet in the Kepler-150 system with a long orbit around its sun. Kepler-150 f takes 637 days to circle its sun, one of the longest orbits for any known system with five or more planets.
Nasa's Kepler Mission had found four other planets in the Kepler-150 system several years ago. All of them have orbits much closer to their sun than the new planet does.“Only by using our new technique of subtracting out the transit signals of known planets could we then actually see it for what it really was.Essentially , it was hiding in plain sight in a forest of other planetary transits,“ said a student of Yale.