A Journey to the Void

Let try to have an idea about the size of the universe we live in. To have some fun let us assume that you are in a very fast space ship. Another assumption is that we will take off from the surface of sun and, that you can live any longer. There will be more assumption which i will assume on the way. :-)
Our spaceship is the fastest spacecraft that can be built by humans and that can reach the speed of 50 Km. per second (The record for fastest speed is for Gallilio spacecraft which reached a speed of 47 Km. / Second, Why speed near to light's is difficult to reach, is the topic we will discus later in the theory of relativity discussion.).So here you are standing on a big star of diameter about 109 times larger than earth and mass 332,900 times of earth's mass, that is called Sun.

First we will explore the solar system and traverse through all its planets. Enough description ! Countdown Starts 10, 9, 8......0.. Zoom.

After the journey of 14 Days the first halt is Mercury.

It is the smallest planet (Radius 2,439 Km., about 1/3 of earth's radius) in the Solar System, orbiting the Sun once every 88 days. It is very cold in night , about -183°C and very hot at day 450°C. Its a metallic planet consisting of about 70% metals. Its mass is about 1/20 of earth's mass.

It will take 10 days to our next planet, Venus. One more assumption here that all planets are aligned.

It is very much like the earth, radius around 5700 Km. and mass about 80% of earth's mass, its year is 225 days long, It has CO2-rich atmosphere which along with sulfur dioxide, generates the strongest greenhouse effect in the Solar System, creating surface temperatures of over 460 °C. This makes the Venus hotter than Mercury. One thing more about it , It rotates in the opposite direction of which all the planet in the solar system rotates. It have volcano on its surface.

10 more days to travel and next planet is our own blue planet. This is an average size planet having radius of 6,371 Km. A very complex system of atmosphere, tectonic plates, water, carbon cycle and magnetic field exists here to make the life possible in our solar system.

The red planet Mars is the next stop which is at 17 days drive from earth (Only with our special spacecraft).

It is approximately half of the radius of Earth (3400 Km.). It is less dense than Earth, in volume it is about 15% of Earth's and in mass about 11% of the earth's. It remains cool and surface temperature varies between -90°C to -5°C.

After this planet you will have no known planet which have the rocky surface. I would like to introduce the assumption that you and your spacecraft can land on any object irrespective of its surface, temperature, atmosphere (whether present or not), gravitational pull or escape velocity.
After 28 days of our take off from Mars we will see the asteroids on the way this region is called asteroid belt of solar system.
One of these asteroid is Ceres which has a radius of 500 Km. and it is a dwarf planet.
You will see the asteroids for 35 more days.

After asteroid belt is over you will travel 66 days more for Jupiter.

Fifth stoppage is Jupiter which is the largest planet in our solar system. It is a whopping gaseous giant. Radius is about 11 times the radius of earth. Its volume is 1321 times of earth's. But it is less dense so its mass is only 318 times of earth's. The atmosphere contains water vapor, methane, ammonia, and silicon-based compounds. Carbon, hydrogen sulfide, ethane, oxygen, phosphine, neon and sulfur also exists here. Its temperature remains about -160°C.

Now be prepared because it will take 150 days for our next planet.
Out next target is Saturn which is the second largest planet of the solar system.

It has gaseous surface and a large number of rocks orbiting around it which looks like rings when seen from far. These are all its moon ranging from a size of 1 Km dia rocks to Mercury size Titan. Titan is believed to have very good condition to support life. One interesting thing about two of its moons, Janus and Epimethius is that they always race each other and each 4 years the moon that is behind catches other and they swap the places. Saturn has radius of about 9 times the radius of earth. and density is much or less similar to that of Jupiter. The atmosphere of Saturn contains of 96% hydrogen and 3.25% helium. Some acetylene, ammonia, phosphine, methane and ethane also exists. Surface temperature is between -190°C to -140°C.

Now rest for one year in your spaceship because till the Uranus there is no halt in between.

Uranus its a white icy looking planet, things looks quite peaceful here, no storms, no cyclones as in its relatives Jupiter and Saturn. Its fourth most massive (After Jupiter, Saturn, Neptune) and third largest planet in the solar system. Its radius is 4 times of the earth's radius. The special property of this planet is its axis of rotation which is about perpendicular to the axis of earth and other planets. Thats why it looks like rounding archery target from earth. Temperature is very low , about -197°C. It consists of water, ammonia, methane and other gases.

Look back to the sun from here and it looks like an ordinary star.
After one year of our take off from Uranus next planet is the last planet of solar system.
What about Pluto? Sorry! its not a planet after 2006 when it was declared a dwarf planer it was also discovered that other Pluto like objects are also orbiting the sun and they all comes in a special region Kupier Belt that is known for the farthest orbiting objects (Like Chiron , Xena etc.) around the sun. Here is Neptune.

Similar in the composition with Uranus ,Neptune is more massive but less larger than Uranus. Its radius is 3.8 time of earth's and its mass is 17 times the mass of earth. Temperature is about -200°C.

Now you have seen all the planets of solar system but you have not crossed it yet, so you will have to travel two years more to cross its boundary which is called Kuiper belt. The Kuiper belt region is similar to the asteroid belt region except most asteroids are made of ice. So beware of these asteroids and drive carefully for next two years.

There is also a gaseous region named Oort cloud after the Kuiper belt it spreads approximately one light years from solar system.
This solar system is about 50 Astronomical unit in radius where 1 Astronomical unit represents 149597871 Km. So the solar system is about 14959787100 Km. span. After the solar system there is a great void , you will not encounter anything bigger until you go 4.2 Light Years (9461 billion kilometers) far. So you will have to travel another 6000 years to go to the closest star Proxima Centuri.
What 6000 years?
Well to answer this question you will have to look at the galaxy we live in. Its a spiral galaxy with a diameter of 100000 Light Years and thickness of 1000 Light Years. It contains 400 billion stars many of them bigger than sun. Its very big coiled structure, hard to imagine. And we live on an outside arm of that milky way. Sometimes in nights when sky is clear you can view the arm of the milky way. It looks like this.

The whole structure of milky way is something like this.

And the average distance between stars here is .25 Light Years.
So if you want to travel the whole galaxy from one end to another with your old fashioned spaceship you will have to travel 30000000000 years.
Its time to change your spacecraft with a new one that can travel with half the speed of light (Its strictly an assumption. No object can approach the speed of light, because as the speed of object approaches to light's speed its mass increases, that can be calculated with the help of Einstein's mass variation formula, and according to this formula when a object reaches the speed of light its mass will be infinite, so it will not be possible to move it further.). So here is your new spacecraft.

Till now I have shown you a very little part of universe to which humankind are familiar with. From now we will travel in light years and will stop only on significant cosmological bodies.
After crossing the Kuiper belt and Oort Cloud  we are now out of our solar system and now we are going to proxima centauri, the closest star to our solar system. It will take only six years to reach this star with our new spacecraft.

Proxima centauri is a red dwarf , that is the term used for the small stars (less than 1/2 mass of the sun's mass.),  it has less hydrogen remaining and its surface temperature is very less (3000 K ) than sun's surface temperature (5500 K). Most of the star you encounter in the universe are red dwarf stars. Besides this there are brown dwarf and white dwarf stars. In ancient Greek mythology Dwarf were the mystical human like creatures who were associated with metallurgy. Dwarf stars do the metallurgy, they crate metals in their core, this is a whole new story about the stars being a dwarf which I will say later. Proxima centuari is orbits around a common center of mass of proxima and alpha centuari. These type of stars are called binary stars.

Now let us explore our galaxy "Milky Way".This is a barred spiral galaxy (That is the tern used for the spiral galaxies having the bas made of stars in the center.), 100000 light years in diameter a and from here it will take 100000 years to reach its center where there is a big black hole. We will encounter so many dwarfs, nebula, supernovas and aliens in the way if we are lucky. We are on the orion arm and based on the map of our galaxy below you can figure out which direction to go.

In the way we will encounter many star clusters , local bubbles of many light years wide. After a good 200000 years of travel from our space ship we have now crossed our galaxy. I did not provided much information about the objects in the way because I don't know much about them either. You can see the strange names of the star clusters and nebula.

Now time to see the other galaxies around.

There is a galaxy named Andromeda which is 2500000 light years away and slightly greater than our milky way.

There are billions of galaxies like this , they come in three flavors spirals, elliptical, irregulars.
And number of intelligent lives?

Well  !! based on theoretical analysis there are trillions of intelligent lives out there.
Now I give you the whole dimensions of universe you are going to travel. It spreads 27.4 billion Light years across. If you want to go to the end of the universe you will have to travel about 13.7 billion Light Years. And if you are travelling with your spaceship which travels at half the speed of light; you will never reach the end even if you are immortal.
Why?
Because it is expanding with the speed of light.
So to reach at the end of the universe you will have to invent a new technology by which you can be transferred very fast. Slightly more than the speed of light.
Suppose we got this technology.
Now will you see the end of the universe.
No!!
Why?
Because as soon as you will cross the boundary (Sorry to use this word, it has no meaning here) of the universe  you will find yourself inserted in to universe from opposite side.
Because there is nowhere to go outside the universe.
The only "where"(space) we have is created by the universe itself. Our scientific laws are limited by it, for it.
So you can never quit the game.