Somewhere outside the Schwarzschild radius of every black hole is a region in which the path of incoming photons is 'bent' 180 degrees and they are sent back roughly in the direction from which they came. In my mind this means that some infinitesimally small portion of the photons that fall on the earth every day were reflected from the earth ~50K years ago and sent in the direction of the black hole at the center of…
I have followed the same idea regarding radio waves. Would it be possible to travel far enough out to receive radio or TV broadcasts from WWII? Presumably all that information in the form of waves is still out there (assuming it hasn't been too distorted by inference, or far too small of an amplitude).
Somewhere outside the Schwarzschild radius of every black hole is a region in which the path of incoming photons is 'bent' 180 degrees and they are sent back roughly in the direction from which they came. In my mind this means that some infinitesimally small portion of the photons that fall on the earth every day were reflected from the earth ~50K years ago and sent in the direction of the black hole at the center of…
I have followed the same idea regarding radio waves. Would it be possible to travel far enough out to receive radio or TV broadcasts from WWII? Presumably all that information in the form of waves is still out there (assuming it hasn't been too distorted by inference, or far too small of an amplitude).
Somewhere outside the Schwarzschild radius of every black hole is a region in which the path of incoming photons is 'bent' 180 degrees and they are sent back roughly in the direction from which they came. In my mind this means that some infinitesimally small portion of the photons that fall on the earth every day were reflected from the earth ~50K years ago and sent in the direction of the black hole at the center of…
I have followed the same idea regarding radio waves. Would it be possible to travel far enough out to receive radio or TV broadcasts from WWII? Presumably all that information in the form of waves is still out there (assuming it hasn't been too distorted by inference, or far too small of an amplitude).
I think that signal strength would decrease along the lines of the inverse square, so after you're some distance out, depending on the initial signal strength you'd find it had decayed to a level indistinguishable from background noise.
The majority of flora we see now also evolved very late. The dinosaurs probably saw and fed on Conifers, Cycadophytes and Ferns. Grass and Modern leafed flora evolved much later.
You can see what forests might have looked like 100mm years ago by going to New Zealand, which split off from the Australian landmass about that long ago. The native flora consists of a lot of ferns, and almost entirely evergreen plants. Flowers are uncommon and primitive, most plants are pollinated and spread by birds. The only native grasses are tussocks.
Head down to Curio Bay and see the remains of a forest from 180mya, too.
Plates which are separating let molten rock from the mantle up, where it cools hardens. Any rock which can be magnetised (iron) is aligned with the Earth's magnetic field when molten, and gets fixed that way. The magnetic field swaps every 10,000 years or so [https://en.wikipedia.org/wiki/Geomagnetic_reversal], so you get a stripey effect.
Working our more precised dates for the magnetic swaps is a matter of slow and painstaking correlation with other bits of evidence: dating of radioactive elements, tree rings, rock layers, the temperature of the Earth, composition of gas bubbles trapped in rock and ice.
Last week I was in the field digging dinosaurs in Montana, when one of the dig leaders mentioned there was no grass back then, just lots of ferns, because grass hadn't evolved yet. It kind of blew my mind that for most of dinosaurs, there was just a lot of leafs and ferns. Here's some pictures for context ( https://imgur.com/a/rE5wwc4 ), when you're out where most dino bones are found, you forget that it may have bee…
There wasn't even grass in South Africa until humans brought it there. Surprised me too.
That's pretty cool. I have two suggestions, if the developer is seeing this: - Mark the North and South poles. For someone unfamiliar with the past continental layouts, it's easy to get a bit disoriented . I would find a location on the globe, jump back in time, rotate the globe a bit to look around, then jump further back in time and then start to get disoriented as to where on earth the details I'm looking at are.…
It would also be really useful if night could be turned off, and if the gimbal lock rotation issues (I'm guessing) could be avoided (with quaternions?).
Somewhere outside the Schwarzschild radius of every black hole is a region in which the path of incoming photons is 'bent' 180 degrees and they are sent back roughly in the direction from which they came. In my mind this means that some infinitesimally small portion of the photons that fall on the earth every day were reflected from the earth ~50K years ago and sent in the direction of the black hole at the center of…
Most black holes, especially ones at the heart of galaxies, are surrounded by huge clouds of dust and gas, and their own accretion disks. Also even for a bare black hole, it's gravity field won't be perfectly uniform to any image would be hugely distorted (like a lens made of poor quality uneven glass). On top of that as photons transit through the gravity field, even if that was perfectly uniform photons on slightly different paths would have their wavelengths stretched different amounts causing diffraction smearing the image. Finally the light path would have to be pretty close to the black hole to slingshot all the way round it, so the gravitational gradient is going to be very steep, meaning all of these effects are going to be very severe. In reality, even for a bare nonrotating black hole (much worse effects if it's rotating), which isn't really a thing as far as we know, the resulting signal is unlikely to be distinguishable from random noise.
There wasn't even grass in South Africa until humans brought it there. Surprised me too.
Really? It doesn't seem to be true: http://rstb.royalsocietypublishing.org/content/371/1696/2015... talks about grasslands in South Africa 1-2 million years ago, well before humans existed.
OK, it seems I misunderstood because I don't know much about grass. It seems there was some grass there a long time ago, but there is also a lot of "alien grass" that was introduced to the Cape region by humans. The alien grass is considered invasive and outcompetes the natural vegetation there which is called fynbos.
Somewhere outside the Schwarzschild radius of every black hole is a region in which the path of incoming photons is 'bent' 180 degrees and they are sent back roughly in the direction from which they came. In my mind this means that some infinitesimally small portion of the photons that fall on the earth every day were reflected from the earth ~50K years ago and sent in the direction of the black hole at the center of…
The earth will have moved from its original position, so you'd probably need to catch photons that were shot off on 'paths' that will intersect your future position, which may not necessarily be photons that were 180-degree reversed.