2. Black Holes and Revelations
Presented in the most depressing colour palette by:
Brandon Saner
David Harrison

3. What are black holes?
Not pink. Not black either. Mostly they’re super long wavelength radio wave coloured. Blah. Blah blah. We all know this. They have, like, mass and angular momentum and charge and stuff.

4. OMG
EQUATIONS!

5. Hawking Radiation 𝑇= ℎ 𝑐 3 16 𝜋 2 𝐺𝑀 𝑘 𝐵 𝜆 𝑚𝑎𝑥 = 0.0029 𝑚∙𝐾 𝑇
𝑇= ℎ 𝑐 𝜋 2 𝐺𝑀 𝑘 𝐵 𝜆 𝑚𝑎𝑥 = 𝑚∙𝐾 𝑇
𝑃= ℎ𝑐 𝜋 2 𝐺 2 𝑀 𝑡 𝑒𝑣 = 2560 𝐺 2 𝑀 3 ℎ 𝑐 4
ℎ=6.626∙ 10 −34 𝐽𝑠 𝑐=2.998 ∙ 𝑚/𝑠
𝐺=6.674 ∙ 10 −11 𝑚 3 𝑘𝑔 −1 𝑠 − 𝑘 𝐵 =1.380 ∙ 10 −23 𝐽/𝐾

6. So wait, stuff can leave black holes?
Yes! Well no. OK, sort of... Some things that don’t really exist can not fall into the black hole, while other things that also don’t exist do fall in. And then the first things start existing for reals because conservation of energy or some such.

7. Well obviously, but what about information?
There are two intriguing hypotheseseseses I am aware of (but do not fully understand): * Information is encoded in the surface of the black hole as perturbations of the event horizon. * Teleportation of quantum states from inside to outside the black hole. In both of these cases, Hawking radiation would carry away the information, meaning the black hole would not have a perfect black body spectrum.

8. News time!
Black holes in galaxies grow faster than expected: "We now know that each ten-fold increase of a galaxy's stellar mass is associated with a much larger 100-fold increase in its black hole mass," Professor Graham said. "This has widespread implications for our understanding of galaxy and black hole coevolution." Sauce:

9. More news!
Youngest black hole found to date. Caught on film by NASA's Chandra X-ray Observatory, the "remnant," or W49B, is seen as a vibrant swirl of blues, greens, yellows, and pinks. As seen from Earth, it is about 1,000-years-old and is located roughly 26,000 light years away. A typical black hole, like SS433, is thought to be between 17,000- and 21,000-years-old, as seen from Earth. Sauce: may-have-uncovered-galaxys-youngest-black-hole/

10. Old news!
Merging black holes: When two black holes collide, space shivers like Jell-O. With the help of a supercomputer to simulate this event, NASA seeks to prove Albert Einstein’s theories and unveil the universe’s secrets. The NASA supercomputer Columbia just performed its largest astrophysical calculation ever: a 3D simulation of two black holes merging. Sauce: simulated/

12. Preblom?
Derive a formula for the density of a non-rotating black hole. I’ll make it easy for you: 𝑟 𝑠 = 2𝐺𝑀 𝑐 2 , 𝐺=6.674∙ 10 −11 𝑚 3 𝑘𝑔 −1 𝑠 −2 Now find the mass at which a neutron star with 𝜌=2∙ 𝑘𝑔/ 𝑚 3 would collapse to a black hole. 1 𝑀 ⨀ =1.99 ∙ 𝑘𝑔 Find the density of the super-massive black hole at the centre of our galaxy, 𝑀=4.3∙ 10 9 𝑀 ⨀

13. Thank-you sir may I have another!
Assuming you have very good eyes and can see light with an intensity of 10 −12 𝑊/ 𝑚 2 , calculate the distance at which you could just see an evaporating black hole in its final second, additionally assuming all of the output is in the visible range. 𝑡 𝑒𝑣 = 2560 𝐺 2 𝑀 3 ℎ 𝑐 4 ℎ=6.626∙ 10 −34 𝐽𝑠 𝑐=2.998 ∙ 10 8 𝑚/𝑠 𝐺=6.674∙ 10 −11 𝑚 3 𝑘𝑔 −1 𝑠 −2 1 𝑝𝑐=3.086∙ 𝑚