Fun Facts About Astronomy

[Zico]

Did you know there are stars which are nearly 600,000 times as bright as the Sun? Or the sunspots on the surface of the Sun are 3000º C cooler than the other sun surface areas? Surprised! Then read on to know some more fun facts about astronomy...

Astronomy is the scientific study of celestial objects like stars, comets, planets and galaxies. It is derived from Greek words astron and nomos which mean 'star' and 'law' respectively. It is related with formation and development of the universe, motion of celestial objects, evolution, physics and chemistry.

Since the 20th century, the field of astronomy has got divided into two branches: observational and theoretical. Observational astronomy emphasis on acquiring and analyzing the data by using basic principles of physics. Whereas, theoretical astronomy focuses on the development of computer or analytical models to explain astronomical objects and phenomena. Both these branches compliment each other.

Fun Facts About The Sun

* The Sun is 4.5 billion years old and produces 383 billion trillion kilowatts of energy.
* Sunlight takes 8 minutes to reach the Earth and is responsible for the ocean currents and weather patterns on our planet.
* The Earth orbits the Sun in an elliptical uneven orbit and the distance between them varies depending on where the Earth lies in that orbit.
* The Sun is only an average size for a star but still accounts for 98% of the total matter in our solar system.
* The solar winds produced by the Sun extends to about 50AU, where AU is the distance from the Earth to the Sun.
* The lightning in the sky is nearly 3 times hotter than the Sun.

Fun Facts About The Moon

* Moon is the only non-Earth object upon which a man has walked.
* Dr. Eugene Shoemaker's love for the moon was so much that after his death, his ashes were scattered over the moon by the Lunar Prospector spacecraft in 1999.
* The giant footprint left on the moon dust by astronaut Neil Armstrong is believed to be the oldest footprint.
* Every year the moon is moving away from the Earth by 3 cm.

Fun Facts About Stars

* There are nearly 1 x 10 ^22 stars in the universe.
* Some of the stars in the sky are so far that the light from them takes million of years to each us.
* Proxima Centauri is the closest star to our solar system and is nearly 4 light years away.
* Inside the nebula, when gases and dust condense, a new object is formed which is know as protostar.
* Depending upon how hot the white dwarf star is, its color varies from blue, white, yellow, or red.
* Supernova explosions are capable of destroying an entire star.
* Pulsar, a neutron star which was discovered in 1967 emits radio waves.
* Polaris, the north star, is the only star in the sky that doesn't appear to move from night to night.

Fun Facts About Planets

* Mercury is the second smallest planet in the solar system and has no moon. It can get as hot as 800º C and cold as 300º C below zero. One year on Mercury is equal to 88 days on Earth. It is named after the Roman God of Commerce.
* Venus is the only planet that rotates from east to west. A year on this planet is equal to 225 days on Earth.
* Earth is nearly 93 million miles away from the Sun. It takes about 16 million horsepower to break the Earth's gravitational pull.
* According to scientists, in around 5 billion years, a day on Earth will be 48 hours long and somewhere during that time the Sun will explode.
* The planet Neptune was discovered more than150 years ago in 1846, and since then it still has to complete an orbit around the Sun, as one Neptune year equals to 165 Earth years.
* Pluto does not have a fixed orbit and its orbit comes in the middle of Neptune's orbit. Also, Pluto's size is very small which made scientists demote it to a dwarf planet status.

Astronomy can be considered as an interesting science filled with many fun and interesting facts. Whether its the size or temperature of a star, the Sun, distant planets - anything and everything once discovered is recorded. This information can be retrieved to entertain and enlighten people.

From: http://www.buzzle.com/articles/fun-f...astronomy.html

[Sampharo]

SInce you are into astronomy. I had A BURNING question to know:

Scientists state the following three as FACT:
1- Nothing moves faster than the speed of light.
2- Universe is 13 to 14 billion years old.
3- The farthest object we see right now appears at 20 billion lightyears away.

This just doesn't add up!! How can the universe exist from 14 billion years ago, yet there are stars we are seeing now the light of stars that are 20 billion lightyears away, which means that if they moved AT the speed of light, (and of course they actually don't even move at 1/1000 of that), they would have had to go through the Big Bang, get 20 billion lightyears away, light emitting, and that light travelling back to us at the speed of ..duh... light, therefore taking another 20 billion years to reach us, putting the minimum timeline (assuming again that the star in question is moving at the speed of light, and therefore we wouldn't see it anyway) at 20 + 20 or 40 billion years. How can the universe be 13 to 14 billion years old then?

[peaceandlove]

Thanks for sharing

[~Raynn~]

How can the universe be 13 to 14 billion years old then?

Lol, I guess this isn't your usual speed = distance/time, because yeah, at first glance this seems grossly wrong...check these out:
Observable Universe
Metric Expansion of Space

The age of the universe is about 13.7 billion years, but due to the expansion of space we are now observing objects that are now considerably farther away than a static 13.7 billion light-years distance. The edge of the observable universe is now located about 46.5 billion light-years away.
---
While it is commonly understood that nothing travels faster than light, it is a common misconception that the radius of the observable universe must therefore amount to only 13.7 billion light-years. This reasoning only makes sense if the universe is the flat spacetime of special relativity; in the real universe, spacetime is highly curved on cosmological scales, which means that 3-space (which is roughly flat) is expanding, as evidenced by Hubble's law. Distances obtained as the speed of light multiplied by a cosmological time interval have no direct physical significance.
---
While special relativity constrains objects in the universe from moving faster than the speed of light with respect to each other, there is no such theoretical constraint when space itself is expanding. It is thus possible for two very distant objects to be moving away from each other at greater than the speed of light (meaning that one cannot be observed from the other). The size of the observable universe could thus be smaller than the entire universe.

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[Sampharo]

It is thus possible for two very distant objects to be moving away from each other at greater than the speed of light (meaning that one cannot be observed from the other). The size of the observable universe could thus be smaller than the entire universe.

Even though this started like it was going to answer, it didn't, it actually made the story even worse for the Big Bang/13.5 billion years old universe. If the observable universe is smaller than the current one, then there is stuff we don't see, which somehow got there. If the Big Bang pushed things out, then again the maximum speed those objects can be moving in relation to the space of existence is 0.99 of the speed of light. Even if we at one absolute edge of the universe and moving at 0.99 the speed of light (which we're not), and that object which is at 46 billion lightyears away is moving the other way at also that same speed, necessarily the relative velocity could not be more than 1.99 of lightspeed, and STILL would mean that the object emitting that light we see, would have emitted that light 46.5 billion years ago because light travels constantly. So there is no way the universe could be 13.5 billion years if we see a fully formed star (or was it a quasar?! not sure) that is 46.5 billion years old, let alone how long it has been there forming. Why are they preaching this 13.7 billion years then?

[~Raynn~]

If the Big Bang pushed things out, then again the maximum speed those objects can be moving in relation to the space of existence is 0.99 of the speed of light. Even if we at one absolute edge of the universe and moving at 0.99 the speed of light (which we're not), and that object which is at 46 billion lightyears away is moving the other way at also that same speed, necessarily the relative velocity could not be more than 1.99 of lightspeed, and STILL would mean that the object emitting that light we see, would have emitted that light 46.5 billion years ago because light travels constantly.

That's the whole crux of the idea...the velocity of the quasar or whatever with relation to the observer is not limited to twice the speed of light...it's accepted that it is possible for the distance between two points in the universe to increase at a rate greater than that at which light can travel this distance - the expansion of space doesn't have to obey the same rules as matter or radiation, lol. Apparently, the concept of 'comoving distance' is used, to correct the actual distance by a certain scale factor to take into account expansion, and time dilation, if we're gonna be dealing with relativistic speeds...

So there is no way the universe could be 13.5 billion years if we see a fully formed star (or was it a quasar?! not sure) that is 46.5 billion years old, let alone how long it has been there forming. Why are they preaching this 13.7 billion years then?

Mmm, they're definitely not saying the quasar they're seeing is 46.5 billion years old...following from the above, its distance isn't proportional to its age. I do understand what you mean, though...how can they say that the universe is a certain age when they believe the observable universe is probably smaller than the actual universe? They don't claim to know its exact size, though, and I'm sure there's evidence besides the distance to the furthest observed object, with which they arrived at this age...redshift, etc, although that kinda uses distance too...

To be honest, theoretical physics has always seemed to me to involve a lot of making assumptions, with which you can make further assumptions, which are in turn used to back up your initial assumptions, lol...

[Sampharo]

Apparently, the concept of 'comoving distance' is used, to correct the actual distance by a certain scale factor to take into account expansion, and time dilation, if we're gonna be dealing with relativistic speeds

Sounds to me that they're just trying not to say "We don't really know", because that sounds like bending and creating new laws of physics just to avoid saying "we got it wrong" :D

Mmm, they're definitely not saying the quasar they're seeing is 46.5 billion years old...following from the above, its distance isn't proportional to its age.

Yes it has to be, if we see the light and measure it's coming from 46.5 lightyears away, then the light beam and particles have been covering the distance for that time, and regardless of what they say about comoving space and all that, light is light and THAT will move at lightspeed through space regardless. If the light is 46.5 billion lightyears away, then (forget the quasar or the star for now if you wish) the LIGHT emitted 46.5 billion years ago and was moving for that time through space (bent or straight, doesn't affect its age, because time warping is a theory that applies to physical objects and not light itself) got to us after travelling such a distance and time. There is no sense then to say the universe is 13.7 billion years old when there is evidence of a star or quasar light that is 46.5 billion years old, right?

What I am suspecting is just the scientific community doesn't have a clue and are trying to find something new to fit :bump1: before admitting they were wrong about the age of the universe or the distances measured. :hmm: Something's gotta give!

[~Raynn~]

Sounds to me that they're just trying not to say "We don't really know", because that sounds like bending and creating new laws of physics just to avoid saying "we got it wrong" :D

Lol, I knowww, but they use such constant correction factors in all sorts of fields, and they're perfectly in line with observational evidence...

Yes it has to be, if we see the light and measure it's coming from 46.5 lightyears away, then the light beam and particles have been covering the distance for that time, and regardless of what they say about comoving space and all that, light is light and THAT will move at lightspeed through space regardless. If the light is 46.5 billion lightyears away, then (forget the quasar or the star for now if you wish) the LIGHT emitted 46.5 billion years ago and was moving for that time through space (bent or straight, doesn't affect its age, because time warping is a theory that applies to physical objects and not light itself) got to us after travelling such a distance and time. There is no sense then to say the universe is 13.7 billion years old when there is evidence of a star or quasar light that is 46.5 billion years old, right?

Noooo, this'll never make sense unless we reconciliate with the idea that the distance between two objects can increase at faster than the speed of light. Forget about light, or anything else, traveling between these objects; we're not saying they're breaking any rules. The rate of expansion of space itself, though, doesn't have to obey special relativity! (And this rate wasn't decided simply based on the suspected age and size of the universe, but by considering inertia/ the observed mass of the universe, for example.)

What I am suspecting is just the scientific community doesn't have a clue and are trying to find something new to fit :bump1: before admitting they were wrong about the age of the universe or the distances measured. :hmm: Something's gotta give!

:giggling: Perhaps, but in defence of the scientific community, lol, they have to admit they're wrong pretty often. If they found this to be such an unresolvable inconsistency, why wouldn't they just quote the age as 46.5 billion years??

[Sampharo]

If they found this to be such an unresolvable inconsistency, why wouldn't they just quote the age as 46.5 billion years??

:thumbs_up Exactly! That's what I am talking about. They can just say that. But I think there is a bit of pride and the matter of that the scientists who somehow "measured" the 46.5 billion lightyear distance are not the same as the one who "measured" the 13.7 billion year age of the universe, and they're both saying "Ze ozer group are ze crazee onez" (Bad attempt at mimicing french/germans/swiss speaking english) :D

[~Raynn~]

:thumbs_up Exactly! That's what I am talking about. They can just say that. But I think there is a bit of pride and the matter of that the scientists who somehow "measured" the 46.5 billion lightyear distance are not the same as the one who "measured" the 13.7 billion year age of the universe, and they're both saying "Ze ozer group are ze crazee onez" (Bad attempt at mimicing french/germans/swiss speaking english) :D

(I can practically hear the bad accent :p)
I actually came across a brief mention of this stuff in my textbook today:

...With red-shift interpreted as recession velocity:

Recession velocity [of distant galaxies] = H * distance to galaxy

The constant H became the Hubble Constant. The bigger the Hubble Constant, the faster the Universe expands, and the younger it must be to have got to its present size. So the Hubble Constant tells you the time scale for the Universe. This time is just its reciprocal 1/H. The Universe must be younger than this time, because gravity will have slowed the expansion down, the rate being higher nearer the beginning of the expansion.

This fact made it very embarrassing for astronomers to find that the first estimates of the Hubble Constant made the Universe much too young. Up until the 1960s the Universe seemed to be younger than the Earth! As the distance scale was revised, so the estimated age rose. Today, settling around a Hubble time of about 14 thousand million years, it's still an awkward fact that there are star clusters which seem to be a bit older than this.

Lol. The first part suggests there's also some kind of upper limit to the age, from the evidence we have...but baasically, this gives me the impression that they're not really sure about anything...;D.
Personally, I think their explanation of the expansion of space is acceptable, even though it seems rather like a loophole...and as far as I know, there's no disagreement over the age; everybody seems to be getting the same crazy measurements. All they can do is work with what they've got :exhausted.

[Whatsthepoint]

This seems a good place to produce the millionth post.

[Sampharo]

Three months away? You're optimistic. :)