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The latest results show the universe is flat, at least pretty much so. WMAP results indicate it is flat within an error of 0.5%. So if you would never come back to your starting point.

Ok, thanks for that, it was just something I was told in a physics lesson a year or to ago: you could never reach an 'end' to our universe, no matter how fast you were travelling, so eventually you would come back to the same place so I presumed it was round :).

Sion

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There is theory and there is hypothesis. Most scientific theories, perhaps all, are born when a scientist produces an hypothesis, an idea of something that might be the case. The hypothesis is tested in one and ideally two ways. 1) It is tested against what has already been observed and is discarded if there is a single clear contrary observation. 2) It is invited to make predictions. These will not yet have been looked for in observations because the idea is new, but the theory will gain much credibility if what it has predicted is found to be the case. If the hypothesis passes these tests it is promoted to a theory. So the OP has produced an hypothesis, not a theory. This is not semantics. It is not semantics to say a tree is not an elephant. We have different words for different things for a good reason. It allows us to talk sense!

So in this case the key observation was Edwin Hubble's. Galaxies at double the distance are moving away from us at double the speed of the nearer ones in whatever direction we look. If they were moving towards us in one direction and away from us in the other direction then the best explanation would be that we were moving relative to the rest of the galaxxies in a clear direction. That is not the case. The other explanation would be that we were in the middle of an explosion but that requires us to believe theat the Milky Way is absolutely unique among the 100000000000 galaxies that are out there. Common sense says 'unlikely.'

Now to move from hypothesis to theory the OP has to find an observation to confirm that the whole universe (which is not the whole universe any more because there is something in which it is moving) is moving towards something in this so far unseen meta-universe. Now that's going to be difficult! How can we say we are moving toowards something that is outside our universe and that we cannot see? And why would we say that?

The Cosmic microwave background shows no directional red or blueshift whatever. It is no bluer in front of us, so to speak, than behind us. So why would we think we were going in a particuar direction?

Olly

Please excuse typos. French keyboard. Now that IS another universe!!!

Edited by ollypenrice

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hey, I just had a silly thought, remember the days when we thought the earth was flat, then the discovery came that the earth was round, imagine this, all planets around, ok apart from the small percent, what if, and I mean what if the universe was a gigantic ball, we dont drop o the edge of the universe but carry on until we come a complete circle, however as the universe is so huge we can never rreturn to the same spot. No one has the answer to whether its a continued or joint, a piece of string has to have a start middle and end unless its a circle. Nice thought, as no one has travelled that distance we will never know, scratch your head on that one

We never did think the Earth was flat, at least not since we started to write things down and communicate widely. The ancient civilizations all knew it was spherical, or roughly so.

Olly

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I was thinking of Christopher Columbus lol

In the time of Columbus, folks knew that the world was round. They also knew that Columbus's maps and calculations were wrong, and that "the East" was a lot farther west than Columbus thought. So far west, in fact, that sailing west to "the East" was a practical impossibility. This was the reason that Columbus had trouble finding backing for his planned expeditions, i.e., the myth that Columbus had trouble finding backing because folks thought the world was flat is just that, a myth.

From http://en.wikipedia....topher_Columbus :

Washington Irving's 1828 biography of Columbus popularized the idea that Columbus had difficulty obtaining support for his plan because many Catholic theologians insisted that the Earth was flat.[25] In fact, most educated Westerners had understood that the Earth was spherical at least since the time of Aristotle, who lived in the 4th century BC and whose works were widely studied and revered in Medieval Europe.[26] The sphericity of the Earth is also accounted for in the work of Ptolemy, on which ancient astronomy was largely based. Christian writers whose works clearly reflect the conviction that the Earth is spherical include Saint Bede the Venerable in his Reckoning of Time, written around AD 723. In Columbus's time, the techniques of celestial navigation, which use the position of the sun and the stars in the sky, together with the understanding that the Earth is a sphere, had long been in use by astronomers and were beginning to be implemented by mariners.[27]

Where Columbus did differ from the view accepted by scholars in his day was in his estimate of the westward distance from Europe to Asia. Columbus's ideas in this regard were based on three factors: his low estimate of the size of the Earth, his high estimate of the size of the Eurasian landmass, and his belief that Japan and other inhabited islands lay far to the east of the coast of China. In all three of these issues Columbus was both wrong and at odds with the scholarly consensus of his day. ...

Columbus therefore estimated the distance from the Canary Islands to Japan to be about 3,000 Italian miles (3,700 km, or 2,300 statute miles), while the correct figure is 19,600 km (12,200 mi)[citation needed], or about 12,000 km along a great circle. No ship in the 15th century could carry enough food and fresh water for such a long voyage and the dangers involved in navigating through the uncharted ocean would have been formidable. Most European navigators reasonably concluded that a westward voyage from Europe to Asia was unfeasible. The Catholic Monarchs, however, having completed an expensive war in the Iberian Peninsula, were desperate for a competitive edge over other European countries in the quest for trade with the Indies. Columbus promised such an advantage.

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Yup, the Columbus myth is widespread but false. Several simple observations confirmed the spherical earth.

- Sailing south, northern constellations set and new ones appeared in the south.

-The masts of ships rose above the horizon as they approached. (I need to check this one but I've read it.)

-In lunar eclipse the curved shadow of the Earth could be seen on the moon.

Eratosthenes (died 195 BC) had derived a remarkably accurate circumference for the earth. We don't know exactly how accurate because his unit of distance was the stade for which no accurate calibration exists but it was a very good estimate.

Olly

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According to these people the Earth is very much flat ;) ...

http://www.theflatea...title=Main_Page

Heard of this before but never actually visited. Do these people actually believe what they are saying or is it a very clever joke I don't get?

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Heard of this before but never actually visited. Do these people actually believe what they are saying or is it a very clever joke I don't get?

lol, I have no idea whether they are trying to convince us, themselves or what.

http://theflatearthsociety.org/cms/

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Heard of this before but never actually visited. Do these people actually believe what they are saying or is it a very clever joke I don't get?

So you think that their joke falls flat? :grin:

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Full of Trolls, I'd avoid the forums on there. How people can seriously believe the Earth is flat, with all the overwhelming evidence to the contrary is beyond me.

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The latest results show the universe is flat, at least pretty much so. WMAP results indicate it is flat within an error of 0.5%. So if you would never come back to your starting point.

Question if the universe was big enough surely it would appear flat even given scientific equipment?

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Its measured using the CMB, which comes from everywhere in the universe, so its not like its just being checked between Cambridge and Oxford. :)

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I am still convinced the universe is a gigantic ball, but what puzzles me, is this, the universe is expanding but what into, is beyond the edge of the universe black, white, any other colour, is it empty or is there something there?

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The universe isn't expanding into anything, if we believe it is infinitely big, but the space between things in the universe is getting larger, even though they are staying in the same place. The best description I heard was that it is like baking something from dough that had raisins in. Each raisin doesn't move but as it is getting baked the dough itself is expanding so the space between the raisins is increasing.

If you want to believe that the universe is finitely big then we cannot say what the universe is expanding into because we are in the universe, the same way we don't know exactly how many arms the milky way has because we are part of it and cannot see 'through' it.

HTH,

Sion

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I am still convinced the universe is a gigantic ball, but what puzzles me, is this, the universe is expanding but what into, is beyond the edge of the universe black, white, any other colour, is it empty or is there something there?

If the universe is expanding into something it is isn't the universe. The universe would be whatever it were expanding into...

'All that there is' is expanding. Personally I don't have a problem with that, though I have plenty of problems with other bits!

The Universe of the BB isn't a ball. It may have some ball-like characteristics but it seems more likely to be saddle shaped, though 'saddle shaped' is just an analogy. The trouble is, our minds want to create a miniature model universe which we can, like a ball or a saddle, hold in our hands. This cannot work because it involves looking at our model from the outside and in the case of the universe this is meaningless because, unlike any other 'object', the universe doesn't have an outside. Attempts to visualize it from the outside are, therefore, doomed to failure. Graphic portrayals of the big bang as an explosion seen from the outside have a lot to answer for because those who create them fail to realize the meaninglessness of portraying them from the outside.

Olly

Edited by ollypenrice

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Here's one for you guy's... Assuming the BB actually happened and it all started from a singularity (which i personally find it hard to get my head round) then did this BB happen in a mass of "dark energy"?... And did this singularity form from a super massive mass?... what created this singularity? how did this singularity contain all the mass in the known and still the unknown universe?... Was our universe born from the collapse of another?.. Are we in the same universe that just keeps collapsing and expanding?,where did this "dark energy" come from?... I wish i knew the answers....I really do.

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One thing which i forgot...... I think BH hold the answers....(Why are some galaxies active and some not?) I may start a new post on this one...

Edited by Vince1963

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Here's an interesting one..

Are there any planets in our Solar System that we haven't discovered yet, and can't because they are not reflective enough, or too far away? Is it possible there is another scorched ball of rock that orbits the Sun closer than Mercury? Or is it possible there is a planet that is much further out than Neptune (mainly because I saw somewhere that they were originally 5 Gas Giants that formed, and one was spun out)?

I was also watching The Wonders of the Solar System yesterday, when it talked about Jupiter and Saturn having formed near the Sun, how is that possible? It seems to contradict everything I know about accretion (ie Heavier elements stay closer to the Sun, lighter elements get thrown out like Hydrogen and Helium and cause Jupiter & Saturn to become massive).

Edited by Naemeth

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"Are there any planets in our Solar System that we haven't discovered yet".... Very likely..

"Is it possible there is another scorched ball of rock that orbits the Sun closer than Mercury"... Very doubtful.. they would have seen it by now.

"when it talked about Jupiter and Saturn having formed near the Sun, how is that possible?".. Apparently so.

I think i'm right on these.. But i maybe corrected LOL

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Phew! That was a very long and very interesting read.

Not sure I'm any the wiser......perhaps we would be wise to remember that todays cutting edge theories often prove to be tomorrows 'has beens'.

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Are there any planets in our Solar System that we haven't discovered yet, and can't because they are not reflective enough, or too far away?

Fairly unlikely I think, nothing significant between the Sun and Neptune anyway - because

  1. Anything big enough to be a planet has to meet certain criteria. The IAU definition says it has to be big enough to collapse under its own gravity to form a sphere, should not be a moon of an existing planet, and has to clear its orbit or other bodies.
  2. Anything big enough will have gravitational pull on other bodies in the system, so we'd know about it.
  3. Anything way out is unlikely to clear its orbit.
  4. Anything way out is also likely to be frozen gases and ices, so quite reflective.
  5. Anything way out would have a hard time forming as a planet so wouldn't be very big.
  6. If it formed further in and got thrown out, it would most likely be on a very eccentric orbit

I was also watching The Wonders of the Solar System yesterday, when it talked about Jupiter and Saturn having formed near the Sun, how is that possible? It seems to contradict everything I know about accretion (ie Heavier elements stay closer to the Sun, lighter elements get thrown out like Hydrogen and Helium and cause Jupiter & Saturn to become massive).

Its more the case that large planets some distance away can collect more H & He because its colder, less solar wind stripping it, and they collect other light ices like methane and ammonia because they are liquid or solid.

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If we assume there is no Planet, or indeed body closer to the Sun than Mercury, I don't believe we can entirely rule out a planet in the suppose "Oort Cloud", as the boundary of which is believed to be some 50,000 AU out. It could possibly be having an effect on Sedna's orbit, as that is highly eccentric, and correct me if I'm wrong, but I don't think the cause of that has been found.

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There could well be some large things outside the Kuiper belt, but I think they'd be unlikely to be classified planets. They would probably have very eccentric orbits, they might be in hydrostatic equilibrium, but probably wouldn't have Cleared the Neighbourhood. I'm sure there are loads more 1000km sized objects to be found around the solar system, but I'd be surprised if we found something the size of one of the gas giants.

It would be rather fun explaining it if we did though!

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