LET'S Put it In Perspective!

[Bobj]

http://www.iceinspace.com.au/forum/attachm...mp;d=1187471950

 

So, now you know.....

[Norrie]

http://www.iceinspace.com.au/forum/attachm...mp;d=1187471950

 

So, now you know.....

 

 

Sooperb Bob...geez I feel so inadequate now !!!!! Thanks for that !!!

[BULLDRAGON]

Soooooooooo (oh absolutely brill Bobj by the way) a question for all the buffs out there

 

If ANTARES is the 15th brightest (biggest??) star in the sky , what is the brightest / biggest?

And further more........what is bigger than that? And even further more ............what is bigger than that? And so on

 

Does infinity play a part in this game? If so , is there life out there and would it be foolish to not believe in other intelligent life beyond our planet?

 

Sorry Bobj for hijacking.............

[Guest Brumagem Phil]

Soooooooooo (oh absolutely brill Bobj by the way) a question for all the buffs out there

 

If ANTARES is the 15th brightest (biggest??) star in the sky , what is the brightest / biggest?

And further more........what is bigger than that? And even further more ............what is bigger than that? And so on

 

Does infinity play a part in this game? If so , is there life out there and would it be foolish to not believe in other intelligent life beyond our planet?

 

Sorry Bobj for hijacking.............

 

Tell you what, pop down to Avis, get yourself a mondeo and go find out...........oh, and take tigger with you as navigator!

[Bobj]

Soooooooooo (oh absolutely brill Bobj by the way) a question for all the buffs out there

 

If ANTARES is the 15th brightest (biggest??) star in the sky , what is the brightest / biggest?

And further more........what is bigger than that? And even further more ............what is bigger than that? And so on

 

Does infinity play a part in this game? If so , is there life out there and would it be foolish to not believe in other intelligent life beyond our planet?

 

Sorry Bobj for hijacking.............

 

As far as life "out there", my opinion , for what it's worth, is, must be!! I read once that there are more stars in the Universe than there are grains of sand on Earth. And, following that, if 100th of 1% were capable of holding planets capable of holding life, that would be more than the grains of sand in the Sahara Desert

 

No problems, mate; it enlarges the discussion.

 

Have a squiz here:

http://www.space.com/scienceastronomy/aas_...ars_050110.html

 

And here:

http://dingo.care2.com/cards/flash/5409/galaxy.swf

Edited August 19, 2007 by Bobj

[Clifftop]

As far as life "out there", my opinion , for what it's worth, is, must be!! I read once that there are more stars in the Universe than there are grains of sand on Earth. And, following that, if 100th of 1% were capable of holding planets capable of holding life, that would be more than the grains of sand in the Sahara Desert

 

No problems, mate; it enlarges the discussion.

 

Have a squiz here:

http://www.space.com/scienceastronomy/aas_...ars_050110.html

 

And here:

http://dingo.care2.com/cards/flash/5409/galaxy.swf

 

 

Bobj,

 

Your a Star your a Star.

 

 

good post mate very interesting.

[poledark]

The chances of life forms like we have on Earth are extremely remote, even if there are billions of stars and planets. It needed a particular set of circumstances like size,temperature,mixture of gas's, plant forms and a host of other conditions all coming together at the same short point in the history of our planet.

 

Just consider how long it took to arrive at that point in time/evolution, and then add in all the other variables, and it is very unlikely that life similar to us has developed anywhere else. Look at Mars for instance, just that tiny bit nearer to the sun, and quite uninhabitable, shift us a few million miles nearer and we all cook, a few million miles further away and we all freeze.

 

I suppose it could also be argued that there is a greater intelligence out there somewhere which decided to use Earth as a playground/laboritory/pleasure garden, and set up the basics as Earth arrived at a suitable point in its existence, and then sat back and watched us evolve......................

 

 

Human life is ultimately doomed to dissapear from the universe as our sun starts to heat up and expand, to finally explode outwards before collapsing back into a frozen lump of material.

 

Den

Edited August 19, 2007 by poledark

[Ken L]

Just consider how long it took to arrive at that point in time/evolution, and then add in all the other variables, and it is very unlikely that life similar to us has developed anywhere else.

 

One of the great suprises about the evolution of life on Earth, is just how quickly it happened after the planet cooled enough for the processes that might lead to life to get going. Given that even most scientists agree that the creation of life is an incredibly unlikely event, it appears to have arrisen on Earth with almost unseemly haste. This speed is one of the main arguments used by those who favour the "panspermia" idea.

 

BTW. Those graphics are great. There's another set somewhere that show the Earth next to sperical bubles representing the volume of the atmosphear and of all the water in the Earths rivers and oceans. That one also makes you sit back and feel a shock as your mind suddenly grasps the perspective.

[Vagabond]

It needed a particular set of circumstances like size,temperature,mixture of gas's,

 

Absolutely right Den, and as further evidence, it seems to have only happened ONCE on Earth. All living material on Earth (micro-organisms, bacteria, fungi, algae, plants and animals) uses the SAME genetic code - derived from the original life-form. There are millions of other genetic code systems that COULD have worked, but which do not exist.

 

If the spontaneous evolution of life was really as easy as Carl Sagan and others would have us believe, then one might have expected it to have occurred more than once on Earth - but there is absolutely no evidence that it did. If a second evolution HAD succeeded and replicated, then there would be traces (in the fossil record or in living organisms) of a "different" genetic code - but there isn't. The chances of the SAME genetic code occuring simultaneously in two different places is like the analogy of chimpanzees, typewriters and the works of Shakespeare, only you would need TWO chimps each of which had produced the same result.

 

Bobj Enjoyed the post, have you ever seen the film "Powers of Ten" ? - a series of graphics that takes you from a football pitch out into space in ten-fold leaps, then back through the football pitch down to sub-atomic space. A bit like Google Earth, but more so.

[corydoras]

Soooooooooo (oh absolutely brill Bobj by the way) a question for all the buffs out there

 

If ANTARES is the 15th brightest (biggest??) star in the sky , what is the brightest / biggest?

And further more........what is bigger than that? And even further more ............what is bigger than that? And so on

 

Does infinity play a part in this game? If so , is there life out there and would it be foolish to not believe in other intelligent life beyond our planet?

 

Sorry Bobj for hijacking.............

Since bobj hasn't answered this yet I'll have a go, Mr M. I'm sure that Bob won't mind just so long as I get it right. I am sure Bob will chip in if i mess things up.

 

When we astronomers are talking about how bright a star is we talk don't talk about it's brightness we talk about it's maginitude. The Ancient Greeks were the first to classify stars this way. They classified the brightest stars they could see as magnitude 1 and the faintest, those they could only just see as magnitude 6. We still work this way today, so you need to get your head round this concept. The LOWER the MAGNITUDE the BRIGHTER the object.

 

Got that, still with me? OK, Good lets move on...

A star that is one magnitude number LOWER than another star is about 2.5 times as bright. Therefore a magnitude 3 star is 2.5 times brighter than a magnitude 4 star. A magnitude 4 star is 2.5 times brighter than a magnitude 5 star. A star that is 5 mags lower than another star is PRECISELY 100 times brighter than the other star. We have changed the Greek system a wee bit to cope with very bright objects, and very very faint objects that they could not see because they did not have telescopes.

 

Got that lot absorbed into your grey matter? Good 'cause now it gets a wee bit harder. Because astronomers actually use two magnitude scales in real life, Apparent Magnitude and Absolute Magnitude. Apparent Magnitude is how bright they appear to us on Earth. The problem with this is that a very dim star that is CLOSE to the earth is often appears brighter than a very bright star that is very DISTANT from the Earth, in the same way that a Xmas tree light bulb held in front of your nose might APPEAR to be a lot brighter than a 500w bulb that was a mile away. To get round this problem astronomers do a little 'mind game' we pretend in our heads to line up all the stars precisely 10 parsecs (a parsec is a unit of distance, you don't need to know what one is, if you want you can google for it but 10 parsecs is about 32.6 light years) then they figure out how bright they would look from that distance.

 

So Mr M now that you have got all that under your hat, I can start to answer your biggest, brightest questions.

 

The brightest star in the sky is Sirius, with an Apparent Magnitude of -1.47. Sirius is about 8.6 light years distant.

The closest star to us is Proxima Centauri, with an Apparent Magnitude of 11.05 and it is about 4.22 light years distant.

 

Now just check those numbers out. Sirius is so bright that its Apparent Magnitude is a negative number (remember the SMALLER the magnitude, the brighter the object) whilst Proxima Centauri has an Apparent Magnitude of more than 11, despite being only half the distance away. Proxima Centauri is a very dim star indeed. You will not see it with the naked eye.

 

OK so if you go out and look up at the night sky Mr M the brightest star you will be able to see is Sirius.

 

Next question what is the biggest star?

The biggest star in the Milky Way is called the Pistol Star. The Pistol Star lies in the constellation of Sagittarius. Its MASS is about 150 Solar Masses. That is to say it contains about 150 times as much 'stuff' as the sun does. Its radius is between 300-340 times the radius of the sun. It is 106 times as luminous as the sun. It is about 25,000 light years distant. It is thought that it generates nearly as much energy as nearly 2,000,000 of our suns. It has an Apparent Magnitude of 4 so it is quite a dim object in the night sky.

 

There is another star that you should know about though Mr M, and Bob would never forgive me for not mentioning it. This one is called Eta Carinae. This is the largest star that we can easily observe. The problem with the Pistol Star is that it is very close to the centre of the Milky Way and there is a lots of gas and dust that obscures our view.

 

Eta Carinae is a Southern Hemisphere star, so Mr M can't see it, but Bob gets a ringside seat. EC is about 100-150 Solar Masses and has an average Apparent Magnitide of 6.21, barely visible to the naked eye. But EC has an incredibly variable Apparent Magnitude this is one of the things that makes EC a very interesting object. In 1677 when EC was discovered by Edmond Halley it was a 4th magnitude star. By 1730 it had brightened considerably. By 1782 it had dimmed again. In 1820 it started to brighten, by 1827 it had brightened 10 fold and by 1843 it had reached an AM of −0.8, the second brightest star after Sirius, but remember Sirius is a mere 8.6 light years distant, wheras EC is some 7000-8000 light years away from the Sun. To put this into some kind of perspective imagine a candle held at 14.5 metres away from your eyes, this represents Sirius. Now imagine another light on the horizon (about 10km) that appears to be as bright as the candle. This represents Eta Carinae.

 

Currently EC has a magnitude brighter than 4.7 so is easily visible to the naked eye but only to Antipodeans like Bob.

Edited August 19, 2007 by corydoras