How Big are Objects Out There

A couple of years ago, I showed this exact video to my nephew and he liked watching it over and over because of the background music. I was showing him how small earth is compared to the rest out there. I remember him asking "Play it again, tito, please".  At his young age of five back then, and I can already see the wonder in his face to see how big other objects are.

The wonder is the same to me until now. I mean, how insignificant are we? Like if the whole universe is a painting on a big canvas, even if the whole earth would disappear, it wouldn't change the painting a tiny bit. This fact never fails to humble me. 

50 Amazing Astronomy Facts

Here is the script from the video:

1. Saturn would float if you would put it in water.
2. If you would place a pinhead sized piece of the Sun on the Earth you would die from standing within 145 km (90 miles) from it.
3. Space is not a complete vacuum, there are about 3 atoms per cubic meter of space.
4. Only 5% of the universe is made up of normal matter, 25% is dark matter and 70% is dark energy.
5. Neutron stars are so dense that a teaspoon of them would be equal to the weight of the entire Earth’s population.
6. The Sun is 400 times larger than the Moon [in diameter not volume] but is 400 times further away from Earth making them appear the same size.
7. The star Lucy in the constellation Centaurus is a huge cosmic diamond of 10 billion trillion trillion carats.
8. Seasons last 21 years on Uranus while each pole has 42 years of sunlight followed by 42 years of darkness.
9. Venus,on the other hand, does not have any seasons at all.
10. 1 year on Mercury consists of less than 2 days on Mercury.
11. There are as many oxygen atoms in a breath as breaths of air in the atmosphere.
12. Helium is the only substance in the universe that cannot be in solid form.It can’t be cold enough.
13. The coldest place in the universe is on Earth. In Wolfgang Ketterles lab in Massachusetts. 0.000000000001 degrees Kelvin.
14. The pistol star is the most luminous star known 10 million times the brightness of the Sun.
15. Saturn’s moon Titan has liquid oceans of natural gas.
16. All the planets are the same age: 4.544 billion years.
17. Earths moon was most likely formed after an early planet named Theia crashed into Earth.
18. 8000 stars are visible with naked eye from Earth. 4000 in each hemisphere, 2000 at daylight and 2000 at night.
19. 90. 99% of all normal matter in the universe is hydrogen.
20. Only 55% of all Americans knows that the Sun is a star.
21. Because of the speed the Sun moves at, solar eclipses can last at most 7 minutes and 58 seconds.
22. Lunar eclipses, however, can last 1 hour and 40 minutes.
23. All the coal, oil, gas, wood and fuel on Earth would only keep the Sun burning for few days.
24. A full moon is nine times brighter than a half moon.
25. When the Moon is directly above your head or if you stand at the equator, you weight slightly less.
26. A single Quasar produce the same amount of energy as 1 trillion suns.
27. Just after the Big Bang, everything in the universe was in liquid form.
28. A planet nicknamed “The Genesis Planet” has been found to be 12.7 billion years old making it the oldest planet found.
29. The shape of the universe looks a lot like a brain cell.[The structure of the universe looks a lot like a brain neuron cells]
30. Every year, the Moon is moving away from Earth by 3.8 centimeters.
31. The Moon spins around its axis in the same time it goes one lap around the Earth which makes us always see the same side of it.
32. Upsilon Andromeda B also only face one side to its star. One side is hot as lava while the other one is cold below freezing.
33. The average galaxy contains “only” 40 billion stars.
34. While in space astronomers can get taller, but at the same time their hearts can get smaller.
35. Mars surface is cowered with iron oxide (rust).
36. Only half a billionth of the energy released by the Sun reaches Earth.
37. Rogue planets are not bound by any star, brown dwarf or another planet which makes them free. float around the galaxy.
38. Sweeps 10 is the planet with the shortest orbital period found. It orbits its star in only 10 hours.
39. 85% of all stars in our galaxy are part of multiple. star systems.
40. Some brown dwarfs have liquid iron rain falling down on them.
41. The light emitting from the Sun is actually 30,000 years old.
42. Of the over 20 million meteors that are observable every day only one or two reach the surface of Earth.
43. The United States have approximately 3,500 astronomers, but over 15,000 astrologers.
44. The closest black hole to Earth is only 1,600 light. years away.
45. There are at least 10^24 stars in the universe.
46. Certain “star quakes” have been found to tear apart the surface of neutron stars.
47. Any free-moving liquid in outer space will form itself into a sphere due to surface tension.
48. The odds of being killed by falling space debris is 1 in 5 billion.
49. Neutron stars can rotate up to 500 times in 1 second.
50. The largest structure found in the universe is the Sloan Great Wall, a super cluster of galaxies 1.37 billion light. years wide.

There are a few I don't quiet understand/agree with yet and I will have to recheck the facts so I highlighted them in red. My additions and corrections are in [brackets]. While in greens are the new ones to me and amazes me.

Diamond Planet 55 Cancri E

Forget about mining small asteroids, as soon as we are done with warp drives we will be off and mining a diamond planet.

Today, Yale University scientists suggests that a rocky planet twice Earth's size orbiting a nearby star is a diamond planet. It is called planet 55 Cancri E orbiting a sun like star that is visible to the naked eye in the constellation of Cancer and is only 40 light years away.

Its radius is twice that of Earth's but it is more dense with a mass 8 times greater. It is also incredibly hot, with temperatures on its surface more than 1,500 Celsius.

"The surface of this planet is likely covered in graphite and diamond rather than water and granite," said Nikku Madhusudhan, Yale researcher.

If diamonds are really girls best friend than this one would surely be the BFF.

Hmmm.. Can you imagine how much we can pawn that planet to the pawnshops?

So, fix those warp drives soon.

Why is the Sky Dark at Night?

It sounds like a stupid question only a dumb little kid would ask. And almost certainly most would answer - "Duh!? Because the sun is away at night!" While that is a simple answer it is only partly correct. It doesn't really entirely answer the question which by the way is nothing but simple. Like if you look at the picture below you would notice that sky is dark even if the sun is shining (yes, that small shiny spot is the sun).

At this point some would explain- "Well, that is because there was no atmosphere from where it was taken for the sun to illuminate." So, now we say that it is the illuminated atmosphere of the Earth that make the daytime bright but not at night. Again, that is a correct but still it will not explain entirely why the night sky is dark.

How about the stars, if there are enough would it not light the sky at night?

It is estimated that if you hold up a grain of sand, the patch of sky it can cover would contain 10,000 galaxies with billions of stars per galaxy. So if there‘s all those stars, why is it so dark at night?

There is an idea called the "dark night sky paradox" or also known as Olbers' paradox after the astronomer Heinrich Olbers. It argues that the dark night sky would conflict that the universe is infinite in space and time. If there are infinite number of stars in this infinite space and infinitely old universe, wouldn't there be a star in every patch of the sky to shine for the day and night?

Here is the mainstream explanation. What we know is that the universe is not infinitely old. It started with a Big Bang 13.7 billion years ago and and stars have existed only for part of that time. We also know that light from these stars travel at a constant speed and that everything in this universe since the start is moving away from each other. This expansion of the universe causes light of stars to redshift(see redshift, Doppler effect) and some would redshift beyond the visible spectrum of the human eye.

In addition, this means that our light from stars within out observable universe, which is smaller that the total universe and that the light from stars further away from us than 13.7 billion light years away, will not have had enough time to reach the Earth.

If all this rather became even more confusing, then watch the minutephysics video below which explains it all.