Can we explore this universe

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In summary, the conversation discusses the limitations of technology in exploring distant star systems, specifically due to the inability of material objects to attain the speed of light. Speculative proposals such as wormholes and warp drives are mentioned as potential solutions, but they come with their own set of problems and limitations. It may be possible to explore the universe through the use of advanced telescopes, but there is a limit to how far we can see due to the expansion of the universe. Overall, the conversation highlights the challenges and complexities of interstellar travel and the vastness of the universe.
  • #1
adilsyyed
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Please ignore my question if you mock over stupid questions...

Keeping in mind:
1) The distance traveled by light in one year is one light year
2) Material objects can not attain the speed of light
3) Solar system is VAST, but at the same time it may be smaller than even a single star far far away from us. Imagine the size of that star system, and then the distance between solar system and that star system (simply billions of billions of billions of light years from us.)

Now the question is :
Can we happen to know what is out there in those systems (with todays technology we can't).
But as stated earliier; it is impossible for a material object to attain the speed of light, so does that mean we can never have the technology to overcome this constraint.

Is it the limit...?
 
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  • #2
To accelerate to the speed of light would require either infinite energy or infinite time so yes, it is the limit. There are speculative proposals to get around this; wormholes and warp drives.

It may be possible to create http://en.wikipedia.org/wiki/Wormhole#Traversable_wormholes" held true).

On the subject of warp drives this paper which is further discussed in this paper proposes ways of getting around the horrendous energy requirements outlined in this paper. The "trick" is to change the warp bubble so that it's exterior radius is microscopic yet the interior radius is large enough to accommodate your vehicle (essentially making a warp bubble that's bigger on the inside than on the out). Apparently this would greatly shrink the amount of energy needed to manageable levels. They don't outline how exactly a shell could be build around a ship in such a fashion nor how the ship could leave.

However neither of these approaches fixes the other problems of a warp bubble such as requiring the construction of an exotic matter shell, superluminal signalling to steer/control the bubble and the huge amount of radiation a warp drive subjects you to. There are some interesting (but technical) objections in this paper that apparently show that a warp drive would only be capable of very low velocities as well as highlighting other problems.

So without exotic matter that may not even exist we are stuck to trying to make slower than light vehicles. To make an interstellar vehicle would be fantastically complex though requiring horrific amounts of energy (even if we used an antimatter rocket we would need potentially thousands-millions of tonnes for a high fraction of c.) as well as a thorough understanding of ecology so as to make a stable environment in a closed system to keep the occupants alive.
 
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  • #3
If we build ever bigger and stronger telescopes, we can explore the universe just fine without going anywhere.

Yes, the distance between stars makes exploration through transportation difficult.. but not impossible. The less massive a particle, the easier it is to accelerate. We as a human species routinely accelerate objects to 99.9999% the speed of light in particle accelerators. I think the future of space exploration is accelerating intelligent microscopic probes close to the speed of light.
 
  • #5
There is, however, a limit to the distance you can 'see' light from. This is because the Universe is expanding and the recession of distant objects causes their light to get 'red shifted' so that its wavelength increases. This red shift eventually turns light into radio waves of increasingly long wavelength and eventually makes them undetectable - so you just couldn't detect things beyond this 'horizon' where the recession speed approaches c (and this c speed IS allowed because it's not objects traveling at c - it's just the space between that is expanding).

I am never very convinced about discussions of wormholes etc., as a way of 'getting about' at FTL speeds. Whilst you could perhaps shove a few particles through a wormhole (if you could just find one) but just imagine how disruptive that could be on a living organism. The distortion to a body in the region of a black hole would be pretty fatal so this wormhole would, I think, need to be very big (millions of km across) so that you could go down the middle and be nowhere near the sides.
 
  • #6
sophiecentaur said:
I am never very convinced about discussions of wormholes etc., as a way of 'getting about' at FTL speeds. Whilst you could perhaps shove a few particles through a wormhole (if you could just find one) but just imagine how disruptive that could be on a living organism. The distortion to a body in the region of a black hole would be pretty fatal so this wormhole would, I think, need to be very big (millions of km across) so that you could go down the middle and be nowhere near the sides.

I'm always sceptical about the horrendous energy requirements, need for exotic matter etc especially since it cost a significant fraction of the worlds richest nation just to put a few canned monkeys on the moon...
 
  • #7
Despite being limited by the speed of light, you could still theoretically get across the entire universe and back in a lifetime while undergoing an acceleration of g or not that much greater. This is because if you're going close enough to the speed of light, relativity causes distances to shrink.

The problem with this is, of course, accelerating at g for decades is, right now, impossible. Perhaps eventually some technology will be developed that allows this, but it will most likely have to rely on some outside power/ mass source.

The other problem is that if you actually did go across the universe and back, the same relativity that shortens your distances also insures that most likely the Earth (and possibly sun/ universe) would not be here anymore.
 
  • #8
I have long pondered this question. I thought about it from the standpoint of a large array of ion drives. Let's say you get enough drives on the back of a ship to produce a .5 g acceleration, and a large fission plant to power all those ion drives. You constant boost ship could reach an external viewed speed of maybe .01 C. But what happens on the ship is the question, how much time dilation, the ions and now a lot heaver, and may continue to produce equal thrust. If ion drives can be improved to get to .9 c, then the ships time could dilate enough to pass the speed of light from the people on the ships point of view. A trip to a star 100 light years away might be just 10 years ships time. The down side is Earth would age almost 150 years in such a trip.
The first step would be a probe launched perpendicular to Earth's southern orbital plane.
The probe would have imaging equipment and a data link laser. The protocol could be any di-phase, manchester2 comes to mind. Observatories in the dry valleys of Antarctica could monitor it's speed by the cell sizes of it's clocked data stream.
the data itself could be images the prob sees, and radiation levels at speed.
might be a good place to start.
 
  • #9
johnbbahm said:
I have long pondered this question. I thought about it from the standpoint of a large array of ion drives. Let's say you get enough drives on the back of a ship to produce a .5 g acceleration, and a large fission plant to power all those ion drives.
etc.
But that doesn't solve the problem of how much energy you need and how much mass you need to eject in order to produce the motive force (even with ion drives). Even a Fusion plant has limits to its energy capacity, too.
The sums give you extremely big numbers for energy requirement, you know, because, in the end, you are approaching E = mcsquared.
 
  • #10
Taking antimatter rockets as having the highest Isp (1megasecond) to get to 99% of the speed of light would take 30 parts fuel to every 1 part ship! Bearing in mind you are still going to need a ship of such huge complexity so as to hold a stable ecology and industrial base that could mean millions of tonnes of antimatter. That's a ridiculous amount of energy.
 
  • #11
With even a short discussion of the Pros, we learn a lot more than weeks of lectures.
Thanks,
 
  • #12
sophiecentaur said:
But that doesn't solve the problem of how much energy you need and how much mass you need to eject in order to produce the motive force (even with ion drives). Even a Fusion plant has limits to its energy capacity, too.
The sums give you extremely big numbers for energy requirement, you know, because, in the end, you are approaching E = mcsquared.

I admit there are quite a few unanswered questions.
Given a fixed power supply and ION drives, the ship should make an asymptotic approach to it's maximum outside observed speed. I was thinking around 30 km/sec. .01c.
From the point of view of the ship, nothing has changed,(maybe a slight doppler shift.)
It would be difficult to go faster the the ions being ejected.
The experiment would come in after the ship hits is maximum outside speed.
How much does time slow down?
based on outside time am I throwing more ions out per second than I was before?
Do those ions have a greater mass, and thus greater thrust?
On earth, is my self clocking data stream showing a broader clock frame?
We think we know some of the answers, but some will wait until we experiment.
 
  • #13
johnbbahm said:
I admit there are quite a few unanswered questions.
Given a fixed power supply and ION drives, the ship should make an asymptotic approach to it's maximum outside observed speed. I was thinking around 30 km/sec. .01c.
From the point of view of the ship, nothing has changed,(maybe a slight doppler shift.)
It would be difficult to go faster the the ions being ejected.
The experiment would come in after the ship hits is maximum outside speed.
How much does time slow down?
based on outside time am I throwing more ions out per second than I was before?
Do those ions have a greater mass, and thus greater thrust?
On earth, is my self clocking data stream showing a broader clock frame?
We think we know some of the answers, but some will wait until we experiment.

You can use an http://www.shellac.org/slu/slutime.html" [Broken] to figure out time dilation. Ion drives obviously need fuel, the limit to how long they can accelerate is determined by the quality of the engineering (keeping an engine going for years takes some good technology) and the amount of fuel available. From the view of the person on the ship nothing changes on the ship, the drive will operate at the same rate as normal. It will appear slower from someone on Earth however.
 
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  • #14
johnbbahm said:
Do those ions have a greater mass, and thus greater thrust?
I may be wrong or interpreted it wrong but this is what I think.
In your frame of reference and that of the ions, nothing has changed in mass. The ions have the same mass as always and are providing the same thrust.
In the frame of reference of someone on Earth, the ions have increased in mass, but so has the ship so acceleration will be unchanged.
 
  • #15
Waterfox said:
I may be wrong or interpreted it wrong but this is what I think.
In your frame of reference and that of the ions, nothing has changed in mass. The ions have the same mass as always and are providing the same thrust.
In the frame of reference of someone on Earth, the ions have increased in mass, but so has the ship so acceleration will be unchanged.

Emphasis mine. You are nearly correct but as I understand it from Earth they would see your acceleration slowed down because everything is slowed down. For me on the ship I may still observe myself accelerating at 10mps2 but for you on Earth I appear to be accelerating at 5mps2 because time dilation means that every minute for me is two for you.

So acceleration doesn't change for the ship but because of time dilation you acceleration is perceived to be slower from an observer at rest.
 
  • #16
Waterfox said:
I may be wrong or interpreted it wrong but this is what I think.
In your frame of reference and that of the ions, nothing has changed in mass. The ions have the same mass as always and are providing the same thrust.
In the frame of reference of someone on Earth, the ions have increased in mass, but so has the ship so acceleration will be unchanged.

I think that you can get over this quandry if you just discuss the momentum given to the ions. That's what would be conserved and provide the added momentum of the ship.
 
  • #17
What about instead of looking at it in terms of distance we look at it in terms of time. To the Universe all points of space and time are the same. If we could make a further point in space closer to us in time we would not need to travel such long distances, which may not be possible at all.

And although we cannot reach the speed of light we can keep getting closer, and eventually we'll reach speeds where we can reach Mars in hours, yet we never come close to the speed of light.
 
  • #18
There is a 'Plan B': Come the day your descendant can upload him/her/itself into a 'computer', that can be sent off at modest sub-light speed, but with the system clock set to 'very slow' so 'apparent' time is tolerable. Yes, okay, that runs right into the Fermi paradox...
 
  • #19
YoungDreamer said:
What about instead of looking at it in terms of distance we look at it in terms of time. To the Universe all points of space and time are the same. If we could make a further point in space closer to us in time we would not need to travel such long distances, which may not be possible at all.

Making a further point in space closer? This has no basis in any contemporary or speculative understanding. The only proposals for something similar are wormholes and warpdrives addressed at the start of this thread.

Nik_2213 said:
There is a 'Plan B': Come the day your descendant can upload him/her/itself into a 'computer', that can be sent off at modest sub-light speed, but with the system clock set to 'very slow' so 'apparent' time is tolerable. Yes, okay, that runs right into the Fermi paradox...

This post is overly speculative. There have been discussions recently on mind uploading here, the issue is too filled in with self appointed experts who know nothing of the field (*cough Kurzweil *cough). It may be possible but it's crackpottery at the moment. If you wan't a specific discussion on this I would suggest you start another thread.
 
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  • #20
ryan_m_b said:
Making a further point in space closer? This has no basis in any contemporary or speculative understanding. The only proposals for something similar are wormholes and warpdrives addressed at the start of this thread.

There is some speculative understanding of this - although purely as a thought experiment. The basic premise involved somehow altering the curvature of space, to "squash" space in front and "expand" it in the back of a space ship. This allows for a stationary object to "move" through space by warping space/time, thereby C can be sidestepped by effectively using controlled expansion.

This is called the Alcubbierre drive and relies on something called the Alcubbierre metric for spacetime modification.This is essentially a "warp drive" and is no way even a theory, it is just a thought expirement but holds for an interesting concept.

Personally I do not think this has any bearing on the real physical world - and I do not think any level of technologies will allow a Star Trek type federation of humans. I just do not think we will EVER have interstellar travel capabilities at any point in our future, I also think it highly unlikely any species anywhere in the U can develop this level of physical control over our U. I do not refute alien lifeforms - I think it numerous in both simople and more advanced forms. However I believe the HUGE distances, IMMENSE energy, UNBELIEVABLE resources and technological deficiencies are all answers to Fermis great question.
 
  • #21
Cosmo Novice said:
There is some speculative understanding of this - although purely as a thought experiment. The basic premise involved somehow altering the curvature of space, to "squash" space in front and "expand" it in the back of a space ship. This allows for a stationary object to "move" through space by warping space/time, thereby C can be sidestepped by effectively using controlled expansion.

This is called the Alcubbierre drive and relies on something called the Alcubbierre metric for spacetime modification.This is essentially a "warp drive" and is no way even a theory, it is just a thought expirement but holds for an interesting concept.

Personally I do not think this has any bearing on the real physical world - and I do not think any level of technologies will allow a Star Trek type federation of humans. I just do not think we will EVER have interstellar travel capabilities at any point in our future, I also think it highly unlikely any species anywhere in the U can develop this level of physical control over our U. I do not refute alien lifeforms - I think it numerous in both simople and more advanced forms. However I believe the HUGE distances, IMMENSE energy, UNBELIEVABLE resources and technological deficiencies are all answers to Fermis great question.

I refer you to my https://www.physicsforums.com/showpost.php?p=3408949&postcount=2". A warp drive would not be the same as pulling the destination closer. I outline in my post papers addressing all the problems with warp drives.
 
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  • #22
ryan_m_b said:
I refer you to my https://www.physicsforums.com/showpost.php?p=3408949&postcount=2". A warp drive would not be the same as pulling the destination closer. I outline in my post papers addressing all the problems with warp drives.

Apologies Ryan was a little bit of a hasty post :)

I have read the links you provded and they are very interesting - i will comment when I have more time and my boss isn't sat watching me :P
 
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  • #23
Cosmo Novice said:
Apologies Ryan was a little bit of a hasty post...i will comment when I have more time and my boss isn't sat watching me :P

That's one of the perks from having an office so far away from your boss's :tongue:
 
  • #24
According to today's knowledge the universe has almost infinite possibilities. There are billions of different stars out there and we have no idea how large the universe truly is. To my knowledge, the furthest galaxy ever seen is 13 billion light years away, known as A1689-ZD1. This galaxy was viewed in 2008 and it took 13 billion years to reach the earth, so we see it as it was at the beginning of the universe, just a few hundred million years after the Big Bang. This is a very short time in comparison to the life of the universe.

It would be an amazing thing if people were able to explore the entire universe. I think that this will be a realistic goal in the future and that one day people may have a much better view of the universe and its contents. I think one of the best ways to do this will end up being through the use of warp holes to achieve the speed of light, for no object can go faster then the speed of light, but perhaps with warp holes, one day people will be able to accomplish this task. An aspect which confirms that people will be able to accomplish this is the thought that all things are connected, which gives the assumption that if everything is connected, then everything can be found with time and hope.
 
  • #25
Cloud Strife said:
According to today's knowledge the universe has almost infinite possibilities.

This is not true, no area of science has evidence indicating infinite possibilities. It's barely logical to guess at how many "possibilities" there are.

There are billions of different stars out there and we have no idea how large the universe truly is. To my knowledge, the furthest galaxy ever seen is 13 billion light years away, known as A1689-ZD1. This galaxy was viewed in 2008 and it took 13 billion years to reach the earth, so we see it as it was at the beginning of the universe, just a few hundred million years after the Big Bang. This is a very short time in comparison to the life of the universe.

We have a reasonable idea as to how big the universe is, see: http://en.wikipedia.org/wiki/Observable_universe. Also A1689-ZD1 formed nearly 700 million years after the Big Bang, one twentieth is not a "very short time".

It would be an amazing thing if people were able to explore the entire universe. I think that this will be a realistic goal in the future and that one day people may have a much better view of the universe and its contents. I think one of the best ways to do this will end up being through the use of warp holes to achieve the speed of light, for no object can go faster then the speed of light, but perhaps with warp holes, one day people will be able to accomplish this task. An aspect which confirms that people will be able to accomplish this is the thought that all things are connected, which gives the assumption that if everything is connected, then everything can be found with time and hope.

I don't know what you mean by "warp holes". I would hazard a guess that you are confusing http://en.wikipedia.org/wiki/Wormhole" [Broken]. Long story short: it doesn't look likely that either of these could exist.

I'm also not sure what you mean by "everything is connected". Are you talking about http://en.wikipedia.org/wiki/Nonlocality" [Broken].
 
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1. Can we explore every corner of the universe?

No, it is not currently possible to explore every corner of the universe. The observable universe is estimated to be about 93 billion light-years in diameter, and there are likely many parts of the universe that are beyond our reach due to the vast distances and limitations of technology.

2. How do we explore the universe?

We explore the universe through various means, including sending spacecraft and telescopes into space, using radio telescopes to gather information, and analyzing data from satellites and probes. Astronomers also use advanced technologies and instruments to study the universe from Earth.

3. Are there any limitations to exploring the universe?

Yes, there are several limitations when it comes to exploring the universe. These include the vast distances between objects, limited technology and resources, and physical and biological limitations of humans in space. Additionally, ethical considerations and the potential impact on other life forms may also limit exploration.

4. What have we discovered through exploring the universe?

We have discovered many things through exploring the universe, including the existence of planets outside our solar system, evidence of dark matter and dark energy, and the expansion of the universe. We have also gained a better understanding of the origins of the universe and the fundamental laws of nature.

5. Is it important to explore the universe?

Yes, exploring the universe is important for several reasons. It allows us to gain a better understanding of our place in the universe, uncover the mysteries of the cosmos, and potentially find answers to some of the biggest questions in science. It also has practical applications, such as advancing technology and inspiring future generations to pursue careers in science and space exploration.

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