The scale of the Universe

fisgon

I've been trying to find a useful image to illustrate the sheer enormity of the scale of the Universe. I remember watching one of those BBC science programmes where Brian Cox illustrated this with a beach and a grain of sand, but I can't remember the comparison he made.

So the question is, if the earth is a grain of sand, and the universe is a beach, how big would the beach need to be? Or do i have it wrong, is it the solar system...(or even our galaxy) that is the grain of sand to make the comparison fit? Would appreciate some knowledgeable input here...

mickmackey1

There is no analogy which makes any sense, all comparisons are illusory, the scale of the universe is totally beyond the comprehension of the human mind.

namloc1980

I posted a thread a while back with a solar system scale on an Irish level:

Irish Solar System

I don't think a scale of the universe is possible, it's just too vast to understand and comprehend.

Mickeroo

THis website has to Solar System to scale too: http://www.scalesolarsystem.66ghz.com/

Great thread there namloc1980, hadn't seen it before.

NoQuarter

This might help: http://scaleofuniverse.com/

fisgon

NoQuarter wrote: »

This might help: http://scaleofuniverse.com/

This is very, very cool.

So by the replies it seems the analogy is not possible. Instead, how about something more measurable...the size of the earth compared to the size of our Galaxy? Does that work with the grain of sand - beach comparison? Just trying to conceptualise our insignificance.

namloc1980

fisgon wrote: »

This is very, very cool.

So by the replies it seems the analogy is not possible. Instead, how about something more measurable...the size of the earth compared to the size of our Galaxy? Does that work with the grain of sand - beach comparison? Just trying to conceptualise our insignificance.

Well let's say that the Earth is a grain of sand 1mm in diamater. The Earth is 12,756km in diameter so reducing it down to 1mm means reducing it be a factor of 12,756,000,000.

The Milky way galaxy is estimated to be 100,000 light years in diameter, a light-year is c.9,460,730,472,580km so 100,000 light-years is 9.46x10<17km. Divide that by the same factor of 12,756,000,000 means that on the scale of the Earth being a grain of sand the Milky way would still be enormous at c.74,166,905km, just over 74 Million Kilometres. :eek: Some beach that would be!!

Ellis Dee

It used to be said that the number of stars in the known universe is probably as great as the number of grains of sand on all of the world's beaches and in all of the deserts on Earth, but some experts (insofar as anyone can really be an expert in this respect) think the actual number of stars is far, far greater than earlier estimated.


To put things in some kind of perspective, one of the Voyager space probes is now approaching the heliopause (the point where the solar wind ceases) after 35 years of voyagering, but it will still be centuries before it reaches the Oort Cloud, which is within the gravitational field of the Sun. It is now about 15 light hours from the Sun, but the most distant galaxies are around 14 billion light years away.

This galaxy, Andromeda, is our "close neighbour", a mere two million or so light years away. That's about twenty million trillion kilometres.

mickmackey1

fisgon wrote: »

How about something more measurable...the size of the earth compared to the size of our Galaxy?

Well let's say you counted one star per second. By the time you had finished counting the stars in just our galaxy you would be... 8000 years old:D

fisgon

namloc1980 wrote: »

Well let's say that the Earth is a grain of sand 1mm in diamater. The Earth is 12,756km in diameter so reducing it down to 1mm means reducing it be a factor of 12,756,000,000.

The Milky way galaxy is estimated to be 100,000 light years in diameter, a light-year is c.9,460,730,472,580km so 100,000 light-years is 9.46x10<17km. Divide that by the same factor of 12,756,000,000 means that on the scale of the Earth being a grain of sand the Milky way would still be enormous at c.74,166,905km, just over 74 Million Kilometres. :eek: Some beach that would be!!

Wow. Maybe the comparison was between the solar system and the Milky Way, with the solar system as the grain of sand. Whatever, we are indeed tiny. Thanks to all for the contributions.

Justin1982

The scale of the universe has to be thought about in terms of light years.

If the Big Bang theory is correct then the universe has been around for 13.75 Billion years approx. and this is as far as humans on Earth can see into space even if telescopes were so powerful that we could see any distance we wanted.

Beyond this visible edge of our universe the universe to the best of our knowledge is infinite in extent, presuming general relativity is correct and presuming that experimental data which gives the matter density of the universe is accurate. There is still a possibility that beyond the visible universe, the matter density is enough to ensure the universe if closed.

ThunderCat

I once saw a science program that gave a description as to the size of our Galaxy. They said that if you represented the entire solar system as the size of a coin, then our galaxy is the size of North America. :eek: