Tomorrow's Monster Telescopes

An interesting article in April's Sky and Tel, Tomorrow's Monster
Telescopes.

A few comments in the article got me thinking.

"The Aperture fever that amateur astronomers often suffer afflicts
professionals too."

"If Extremely Large Telescopes do move beyond the Earth, it's anyones
guess to their size and structure."

Assume that some day unlimited funding and technology will be
available, and that we have the ability to build instruments as big
and optically perfect as we could possible ever want. (Visual light.
Just in case this question develops into a meaningful thread.)

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

Would anyone care to speculate how large that instrument would be?

What would that telescope be capable doing?

Lets also assume this to be cloudy night, wishful sort of thinking
and that there's no reason for anyone to get their nose out of joint
because they don't like the question.

LdB

On Mar 9, 1:57 pm, L D'Bonnie wrote:
An interesting article in April's Sky and Tel, Tomorrow's Monster
Telescopes.

A few comments in the article got me thinking.

"The Aperture fever that amateur astronomers often suffer afflicts
professionals too."

"If Extremely Large Telescopes do move beyond the Earth, it's anyones
guess to their size and structure."


I too saw that cover, and the competing mag with 'Is this the shape of
the universe?', both of which caught my eye- yet neither did I
purchase.
(It was touch & go for a min. though.)

Still, it got me to wondering how much a larger mirror would be useful
vs. many smaller mirrors in a group, esp. something built down here on
the ground.

I would say improvements will better be gained by making a 'Super
Hubble' orbiting telescope instead, and beaming the images back to a
ground station.

Not the same as having the actual electrons hit the back of your eye
but then.....


TBerk

L D'Bonnie wrote:
An interesting article in April's Sky and Tel, Tomorrow's Monster
Telescopes.

A few comments in the article got me thinking.

"The Aperture fever that amateur astronomers often suffer afflicts
professionals too."

"If Extremely Large Telescopes do move beyond the Earth, it's anyones
guess to their size and structure."

Assume that some day unlimited funding and technology will be
available, and that we have the ability to build instruments as big
and optically perfect as we could possible ever want. (Visual light.
Just in case this question develops into a meaningful thread.)

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

Would anyone care to speculate how large that instrument would be?

What would that telescope be capable doing?

Lets also assume this to be cloudy night, wishful sort of thinking
and that there's no reason for anyone to get their nose out of joint
because they don't like the question.

At the point that the telescope is large enough that the limit to its
resolution is the atmosphere of the alien world that its looking at,
then its big enough.
:-)


Shawn

On Sun, 09 Mar 2008 15:57:51 -0500, L D'Bonnie wrote:

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

From a practical standpoint, I'd say no. A bigger aperture means more
resolution, of course. But it also means more light, and that means the
ability to record more rapid events.

In theory, you don't need more resolution when you reach the point where
you can resolve something the wavelength of your light at the edge of
the observable Universe. So in terms of resolution, that could be
considered to define an upper limit on aperture. But somehow I don't
think you were considering mirrors the size of galaxy clusters g.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

--
Posted via a free Usenet account from http://www.teranews.com

In article ,
Chris L Peterson wrote:
On Sun, 09 Mar 2008 15:57:51 -0500, L D'Bonnie wrote:

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

From a practical standpoint, I'd say no. A bigger aperture means more
resolution, of course. But it also means more light, and that means the
ability to record more rapid events.

In theory, you don't need more resolution when you reach the point where
you can resolve something the wavelength of your light at the edge of
the observable Universe. So in terms of resolution, that could be
considered to define an upper limit on aperture. But somehow I don't
think you were considering mirrors the size of galaxy clusters g.

You're thinking in the limits of current technology. If truly
'unlimited technlogy' really was available, it could produce a small
pocket scope able to resolve much smaller objects than a light wavelength,
at the other end of the universe - and that scope would be cheap enough
for kids to be able to afford it.

Consider today's pocket computers which have capabilities far exceeding the
early dinosaur computers of the 1950's ..... truly 'unlimited technology'
would of course be able to bring a similar revolution in telescopes.
How would they work? I have absolutely no idea -- according to our
current understainding, such a device is impossible. But that's just
because our technology is LIMITED by the natural laws. Truly unlimited
technology would not have such limits....

_______________________________________________ __

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

--
Posted via a free Usenet account from http://www.teranews.com



--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

Paul Schlyter wrote:
Consider today's pocket computers which have capabilities far exceeding the
early dinosaur computers of the 1950's ..... truly 'unlimited technology'
would of course be able to bring a similar revolution in telescopes.
How would they work? I have absolutely no idea -- according to our
current understainding, such a device is impossible. But that's just
because our technology is LIMITED by the natural laws. Truly unlimited
technology would not have such limits....

To the extent that natural law is natural law, *all* technology, today
and future, is limited by such law. Because most of our technology is
designed explicitly, today's technology is also limited by our current
understanding of natural law. It could be that the kinds of devices you
have in mind will come about in the future, but if so, they will still
be bound by natural law, even though they probably would defy what we
know today.

In short, outside of our imagination, there is no such thing as "truly
unlimited" technology.

--
Brian Tung
NOTE: Below addresses changing soon...
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html

On Mar 10, 12:43 am, (Paul Schlyter) wrote:
In article ,
Chris L Peterson wrote:

In theory, you don't need more resolution when you reach the point where
you can resolve something the wavelength of your light at the edge of
the observable Universe. So in terms of resolution, that could be
considered to define an upper limit on aperture. But somehow I don't
think you were considering mirrors the size of galaxy clusters g.

You're thinking in the limits of current technology. If truly
'unlimited technlogy' really was available, it could produce a small
pocket scope able to resolve much smaller objects than a light wavelength,
at the other end of the universe - and that scope would be cheap enough
for kids to be able to afford it.

No: unless specified otherwise, "unlimited technology" only means that
anything can be engineered that complies with the *known laws of
physics*. This is because "technology" is distinct from "science", and
because it's not particularly useful to discuss what we could do if
wishes were horses, because the answer, "anything", is already known.

The question of what improvements are possible in telescopes within
the sole constraint of current scientific knowledge, but with
unlimited resources of energy and materials, and the ability to turn
anything that we know could exist into reality, is, on the other hand,
meaningful. So we could talk about the performance of a telescope
whose mirror is, say, as wide as the Moon.

John Savard

On Mon, 10 Mar 2008 07:43:02 GMT, (Paul Schlyter) wrote:

You're thinking in the limits of current technology. If truly
'unlimited technlogy' really was available, it could produce a small
pocket scope able to resolve much smaller objects than a light wavelength,
at the other end of the universe - and that scope would be cheap enough
for kids to be able to afford it.

Consider today's pocket computers which have capabilities far exceeding the
early dinosaur computers of the 1950's ..... truly 'unlimited technology'
would of course be able to bring a similar revolution in telescopes.
How would they work? I have absolutely no idea -- according to our
current understainding, such a device is impossible. But that's just
because our technology is LIMITED by the natural laws. Truly unlimited
technology would not have such limits....

There's a difference between "unlimited technology" and "magic".
Unlimited technology doesn't mean you can do anything, it means that the
laws of nature are your only limits (not, for instance, engineering
limitations). There's absolutely no reason to think that a pocket sized,
optical telescope can achieve arbitrarily fine resolution. And it
certainly can only collect the photons that cross its path, which isn't
very many.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

--
Posted via a free Usenet account from http://www.teranews.com

In article ,
L D'Bonnie wrote:
An interesting article in April's Sky and Tel, Tomorrow's Monster
Telescopes.

A few comments in the article got me thinking.

"The Aperture fever that amateur astronomers often suffer afflicts
professionals too."

"If Extremely Large Telescopes do move beyond the Earth, it's anyones
guess to their size and structure."

Assume that some day unlimited funding and technology will be
available, and that we have the ability to build instruments as big
and optically perfect as we could possible ever want. (Visual light.
Just in case this question develops into a meaningful thread.)

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

With unlimited funding and technology available, why would one limit
oneself to just build a huge telescope? Why not instead build e.g.
a very large number of vehicles which all instantly could travel to
any place in the universe?

Or perhaps one could then transform the universe into something we
would prefer over the existing universe..... why just observe when
we actually can change things?

And, while we're at it, with unlimited technology, why would a telescope
have to be huge? Why not instead build e.g. a small pocket scope
with capabilities exceeding anything we could ever dream of? That
scope would then be able to e.g. resolve small details (e.g. molecules)
on planets in another galaxy! And it would be cheap enough for each
kid to be able to afford one.... compare with e.g. computers, where
the early dinosaur computers did cost millions and each required a
staff of trained engineers to run - today, a kid can easily buy a
home computer with capabilities far exceeding those early dinosaurs...

With truly unlimited funding and unlimited technology, each of these
things would be quite feasible. The reason this is a fantasy is of
course that in real life, both funding and technology will always have
limits. Even if funding would be unlimited, technology for instance
is always limited by the natural laws.




Would anyone care to speculate how large that instrument would be?

What would that telescope be capable doing?

Lets also assume this to be cloudy night, wishful sort of thinking
and that there's no reason for anyone to get their nose out of joint
because they don't like the question.

LdB


--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

Paul Schlyter wrote:

With truly unlimited funding and unlimited technology, each of these
things would be quite feasible. The reason this is a fantasy is of
course that in real life, both funding and technology will always have
limits. Even if funding would be unlimited, technology for instance
is always limited by the natural laws.


We can always dream of a world where it is politically correct to
shoot bean counters on sight.

Perhaps my question should have been more along the lines of
Has nature imposed a limit to the maximum size a telescope could
be, where it would no longer be of any use to build bigger?

LdB