Here's a few facts I learned (or better said - picked-up) during my long-time fascination with the Universe. I am not an expert in any of this, but I like to acquire information. I also like to share with others what I learned. So, here goes ...
1. Universe is big. Really BIG.
To start thinking about the size of the Universe we don't need to immediately start thinking about billions of light-years to have an idea that Universe is really big. For the start, it's enough to think only about the distance between us and the star that is closest to the Earth.
The closest star to the Earth (outside the Sun) is Proxima Centauri, at 4.22 light-years distance. So, how much is a light-year?
Light moves at speed of 300 000 (three-hundredth thousand) kilometers per second. A light-year is a distance light travels in a year. So, by using some math, we get that one light-year is actually 9.461x1012 km, or better said - 9.461 trillion (nine trillion) kilometers.
Hubble's Shot of Proxima Centauri, our Nearest Neighbour.
Credit: ESA/Hubble & NASA. (source)
The fastest man-made object in history is the Voyager 1 probe, which "as of 2013, was moving with a relative velocity to the Sun of about 17030 m/s" (wikipedia). Even at this speed, it would take Voyager 73.000 years to reach the star closest to us. Remember, it's only 4.22 light-years.
And only our galaxy has a diameter of 100 000 light-years.
Humanity knows that universe is at least 91 billion light-years in Diameter. How? Well, because this is actually the size which we can see with any type of light. We calculated that Universe is 13.8 billion years old. And we also know that universe is expanding. As light travels to us, the universe itself expands. The red-shift in the light enables us to calculate when the light was emitted. So, if light left 13 billion years ago, this distance is now 46 billion light-years in either direction.
This is just the size of the Observable Universe. The total size of the Universe is much bigger and also probably Infinite.
Here's a few videos that help to understand this.
I'm not a scientist and I don't claim to understand a lot about this apparently HUGE scientific discovery, but I don't think this should stop me in sharing some videos I watched and articles I read. After all, here I'm assuming the role of a mere messenger, a messenger that was always fascinated by space and science. I also believe that every scientific discovery is a sign of mankind's progress towards a better future.
"This illustration shows the gravitational waves thought to be produced by two orbiting white dwarf stars in a binary system called J0651, according to an August 2012 study."
Credit: NASA - Taken from space.com
Gravitational waves are "ripples" in spacetime which behave like waves when you throw a stone in water, going outwards from the source. Now for the first time this effect has been observed on Earth. See this video from ESA where Gravitational Waves are Simply Explained With A Cube And Marble:
As passionate Twitter users would say "Facebook is for connecting with people you went to high school with. Twitter is for connecting with people you wish you went to high school with".
This is my small collection of interesting twitter accounts you should follow. This is a "No Development" edition, meaning there will be no developers' or IT accounts in here. This is a topic for another post because there are so many "must-follow" developers and development accounts out there. So, on with the list. It is sorted in no particular order.
United Nations - @UN
"The United Nations is an international organization founded in 1945 after WW II by countries committed to maintaining international peace and security, developing friendly relations among nations and promoting social progress, better living standards and human rights."
Gates is a programmer, inventor, former CEO of Microsoft and a philanthropist. Right now he's trying to save the world.
Neil deGrasse Tyson - @neiltyson
Neil deGrasse Tyson is an astrophysicist, cosmologist and author. He tweets great stuff not only about space, but about science and humanity in general.
Continuing to publish videos I think might be useful/inspirational, here's a video where Bill Gates unveils his vision for the world's energy future. Find 30 minutes of free time to hear Bill Gates talk about ecology and climate.
In this TEDx talks video Lucianne Walkowicz explains the importance of preserving our dark night sky from the perils of light pollution and other lesser-known factors. In Lucianne's eyes, "Our night sky is a natural resource, it's like a park you can visit without ever having to travel there."