Darkest Planet

[zak]

when we flash a light over objects it will reflect some of that light even if it is the black coal. such as the eyes of the Hyena in the picture.
7422

but astronomers discovered the darkest planet which are blacker than coal and reflects almost no light:
http://news.nationalgeographic.com/news/2011/08/110812-new-planet-darkest-black-coal-kipping-science-space-kepler/

[danbaron]

Of course, if there was a black hole with a big enough event horizon between the Sun and the Earth, no sunlight would reach Earth at all.

As far as we know, the volume of the matter comprising a black hole is zero (as the dying star begins to shrink, the gravitational force increases, so, it continually shrinks faster and faster - it never slows down, undergoing gravitational collapse, to zero volume and, infinite density - because all of the mass remains), but, the maximum radius at which its escape velocity is greater than the speed of light (its event horizon), may be huge, depending on its mass. I think that inside the event horizon, the space curves from the hole's center, to the event horizon, and back to the hole's center. I don't really understand it. Even though there seems to be no connection between the space inside the event horizon, to the space outside the event horizon, somehow, an object can cross the event horizon from the outside to the inside, but not from the inside to the outside.

Additionally, inside a black hole's event horizon, time stops - if you crossed an event horizon, when one second ticked on your watch, infinity would have passed in the outside universe.

[zak]

astronomers don't know exactly what causes its darkness [[ some have proposed that this darkness may be caused by a huge abundance of gaseous sodium and titanium oxide," Kipping said. "But more likely there is something exotic there that we have not thought of before. ]]


the way they know that it is a dark planet is by measuring how much it dims or brighten while orbitting its star, they detected only the slightest such dimming and brightening, so it is practically reflecs no light.

[danbaron]

It does seem strange that a ball of gas could be black.