Sunday, March 1, 2020

Our Mighty Sun



The Oort Cloud is believed by astronomers to surround the solar system. It is the ultimate outer boundary of our sun’s domain. This cloud is believed to consist of icy planetesimals - cosmic dust/grains. It was named in 1950 after the Dutch astronomer Jan Oort, who worked on this hypothesis.

According to astronomers, the Oort Cloud is a belt which surrounds the sun and the solar system at a distance which begins at about 2,000 Astronomical Units (AUs) and may go as far out as 200,000 AUs.

This is an astounding size. If the Oort Cloud hypothesis is correct, it means that the domain of the solar system is enormous.

Consider this:
One Astronomical Unit is the distance between earth and the sun, which is 150 million kilometers, or 93 million miles. If the Oort Cloud’s outer edge reaches all the way out to 200,000 Astronomical Units from the center of the solar system (the sun) then its diameter is 400,000 AUs.

It takes light 8 minutes to cover one AU (to travel from earth to the sun). As mentioned, the inner rim of the Oort Cloud is 2,000 AUs away from us. So it takes light 16,000 minutes to travel that far, i.e. 11.1 days. The OUTER rim of the Oort Cloud is 200,000 AUs far, i.e. one hundred times further. So for light to travel to the Oort Cloud’s outer edge takes 100 times longer, i.e. 1,111 days or over 3 years. The sun reaches three light years out into space!

In kilometers and miles:

The Oort Cloud’s inner edge: 150 million kilometers x 2,000 = three hundred billion = 300,000,000,000 kilometers, or 186,000,000,000 miles.

The Oort Cloud’s outer edge: One hundred times the figures in the previous paragraph. That is: 30 trillion kilometers = nearly 19 trillion (18,600,000,000, 000) miles.

Time
Distance Traveled by Light
one second
300,000 kilometers or 186 miles
one minute
18 million kilometers or 11 million miles
one hour
1.1 billion kilometers or 670 million miles
one day
25.9 billion kilometers or 16.1 billion miles
one year
9.46 trillion kilometers or 5.9 trillion miles

distance
equivalent
one kilometer
.62 mile
one mile
1.61 kilometer
one AU (Astronomical Unit)
150 million kilometers or 93 million miles or 8 light minutes
one light day
25.9 billion kilometers or 16.1 billion miles or 180 AUs
one light year
9.46 trillion kilometers or 5.9 trillion miles or 65,700 AUs

Now Consider this:

The closest stars to us are Proxima Centauri and its twin neighbors Alpha Centauri A and B - Only 4.2 to 4.3 light years away. Another neighbor is Sirius, which is 8.6 light years away.

Today, some of our manned spacecrafts may be able to travel at, say, 50,000 miles per hour, or    1.2 million miles a day. We can reach the sun in 77 days, i.e. cover one AU in that amount of time.

Proxima Centauri is 4.2 light years away, or 4.2 times 65,700 AUs = 275,940 AUs.

Since it takes us, at best, 77 days to cover one AU, traveling to Proxima Centauri would take us 21,247,380 days = 58,372 years.

This is twice as far into the future as Cro Magnon and Neanderthal men lived in the past.

Astronauts taking a roundtrip would return as far in the future as dinosaurs lived in the past.

But we already know this. It’s long been clear that we are the prisoners of the solar system. That, as long as Einstein rules, telling us that nothing can exceed the speed of light, we are unlikely to ever visit another star.

Let’s say we develop highly advanced rocket technology and manage to speed up human space travel tenfold, to 500,000 miles per hour. We would then be traveling at close to one thousandth the speed of light. This way, we could reach our closest neighbor star in less than 6,000 years - only fifteen hundred years more than the time that has lapsed since the Great Pyramid of Giza was built.

But today, I am writing about the solar system, and its outer belt, the Oort Cloud. Just to travel to the inner border of that asteroid belt, the side closest to us, would require 422 years, traveling at 50,000 miles per hour. At its current speed of about a million miles a day, NASA's Voyager 1 spacecraft won't enter the Oort Cloud for about 500 years. And it won’t exit the outer edge for maybe 50,000 years.

To reach Oort’s outer edge would take one hundred times longer, i.e. 42,000 years. And to traverse the entire Solar system would require twice as long, i.e. 84,000 years.

What is amazing is that some stars are only slightly further than the outer extremity of the Solar system. Or to put this in reverse: The solar system’s sphere of influence reaches out nearly  three quarters of the way to our neighbor stars.

And: It takes light six years to cross the entire Solar system, which is a longer voyage than going to the nearest star!



© Tom Kando 2020;All Rights Reserved

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