How far Neptune is?

Neptune from the eyes of Voyager 2

Do you know what is the farthest planet currently in our solar system? Pluto? No! Pluto is no longer the farthest planet in the solar system. Scientists and astronomers have eventually agreed that Pluto must be excluded from its status as a planet! Now since Pluto has been demoted from its status, Neptune takes the honour as the farthest planet in the solar system.

Does it mean that our solar system has 'shrunk'? Not exactly, the outermost limit of the solar system is not marked by the farthest planet, but by the farthest object that still revolves around the sun. Even though Pluto is no longer classed as a planet, it is still considered as the part of our solar system.

Even if Neptune is our outermost object in the system, our universe is still vast! Now let's see how far Neptue is from the earth! Supposedly that someone wants to 'waste' his time to go to the planet in a rocket with the available current technology, and with the current technology you can travel with the speed of 50 kilometers per second (kps) through the space. First let's see how fast is 50 kps. Actually it gives the figure of 180,000 kilometer per hour (kph) or 112,000 miles per hour (mph), it means that the rocket travels 1,800 times faster than your car dashing at the speed of 100 kph (62 mph)! But don't be too happy so soon, that speed is very slow in the term of vast distance in space! Now let's check the distance between the earth and Neptune, according to the data given in Wikipedia, the average distance between the sun and the planet is 30 Astronomical Unit (AU) approximating ( 4.5 billion kilometers / 2.8 billion miles), meanwhile the distance between the sun and the earth is 1 AU or 150 million kilometers or 93 million miles. Ok, now let's skip the arithmetical headache, it represents the fact enough that the distance between our blue planet and the gas giant Neptune is about 29 AU (4.35 billion kilometers / 2.7 billion miles). Now giving all the data above we can simply calculate that our rocket will reach Neptune from Earth in about 3 years!!

It still doesn't impress you? Ok now wait! We take another example! You know that if you communicate with your friend through your cellphone, you can hear your friend's voice almost instantly as he speaks! That's because the signal between the cells travels almost at the speed of light. But if you (on earth) communicate with someone in Neptune (provided with the most advanced communication technology available today), you might be surprised to find a long delay! Suppose that the communication signal travels at the speed of light or 300,000 kps or 1,080,000,000 kph (the actual speed of the signal of course is slightly less than the speed of light). Now think again that the distance between the earth and Neptune is 4.35 billion kilometers meaning that the signal will reach the earth from Neptune (and vice versa) in about 4 hours! What does it exactly mean? It means that you will hear your friend's voice on your set 4 hours after your friend in Neptune speaks on his set !!! What a delay!!

Well now we can imagine how vast is our solar system. Let alone the whole galaxy or the whole universe considering that our solar system is just a tiny tiny tiny speck in the universe!

(Written by: Yari NK)