Space telescopes

[Dominick]

No less than three space based telescopes are in the news these days. There is the Hubble maintenance mission, and there are two brand new ESA (European Space Agency) projects.

http://news.bbc.co.uk/2/hi/science/nature/8048687.stm
The famous Hubble telescope is now no less than 19 years old and still in working order. It's presently undergoing maintenance by a Space Shuttle crew which will do some repairs and replace one of the auxiliary instruments. I doubt I need to go in much detail over Hubble to a primarily American audience but I'll list some of the Greatest Hits from Hubble in a follow-up post.

http://news.bbc.co.uk/2/hi/science/nature/8046463.stm
And then there's ESA's ambitious project of launching two space telescopes simultaneously, Herschel and Planck, by a classic Ariane V rocket.

They're not optical telescopes though such as Hubble is. Herschel is sensitive to a range of the spectrum from infrared to radiowaves. Its main mission is to look through the objects that gave Hubble such fame.

Planck will observe the microwave range of radiation as a specific task. This is very interesting as the microwave background radiation is the telltale leftover of nothing less than the infamous Big Bang. The indescribably massive energy of that event has over the billions of years been diffused a number of processes not the least of which is simply the expansion of the universe. Presently it is almost uniformly about 2.7 K or -270.45 C (Kelvin is the same scale as Celsius but with its zero point at the absolute minimum temperature which is -273.15 C).

The 'almost' in the previous sentence is crucially important. There are minute differences in this background radiation (to the order of 1 in 10,000). It are precisely these differences that are the reason there are clumps of matter such as stars or planets in existence in the first place. If the Big Bang had given rise to an absolutely uniform diffusion of energy, and thus matter, there would have been no solid objects in the entire universe.

Most of you will know this but just in case: When you look at the image formed by light from space you're not only looking far away but also long ago. Light travels at the speed of light (duh!) and although that's very fast the distances in the universe are so vast even light takes its time. So, the farther you look the longer ago did the things exist that you see.

Planck will now look at the very first stages after the Big Bang. And possibly beyond that. In modern cosmology that is not necessarily a paradox. It's also pretty certain that inflationary theory will be put to the test for the first time. This is a theory that for very good reasons assumes that in the first few fractions of a second after the Big Bang the universe underwent a period of excessive inflation, i.e. that it grew at a rate many many orders of magnitude beyond its present expansion.

Feel free to ask any questions. I know this field very well.

[SMadsen]

Wow, the Herschel/Planck will be launched today? In one to two hours? How cool is that!


Although not in the news recently, perhaps a thread on space telescopes should also include the James Webb Space Telescope. It'll probably be the telescope that most people will hear about after the launch in 2014 as it's an infrared to visible light telescope and will probably be taking the most public-friendly pictures that also made Hubble a household name. Alone the mirror of 6.5 meters compared to Hubble's 2.4 meters mirror is quite an upgrade but the instrumentation will of course also be state of the art and worth a peek (http://jwst.gsfc.nasa.gov/).

[SMadsen]

Here's the countdown: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=16

[Dominick]

It's not the prettiest but arguably the most important Hubble pic: The Deep Field. Everything you see in this pic is a galaxy with each hundreds of billions of stars. Don't be mistaken in thinking that the universe is a crowded place though. On average there are no more than a handful of hydrogen atoms per cubic km.

[Dominick]

This one is important in that it's corroborating evidence for relativity. Because light bends around a center of gravity the objects behind that center are shown mutiple times. This is called gravitational lensing.

[Dominick]

Possibly the most famous one. For a sense of scale of these "pillars" : the entire solar system would fit nicely in each of them.

[Dominick]

And a pretty one. This is the Ring Nebula, well known to backyard astronomers even with modest means. It's a planetary nebula which typically for scientific nomenclature has nothing to do with planets. It's a shell of gas cast off by a star in decline.

[Michael]

Possibly the most famous one. For a sense of scale of these "pillars" : the entire solar system would fit nicely in each of them.
:eek:

What the heck are these? :ummm:

[SMadsen]

Succesfull launch! Video at http://www.youtube.com/watch?v=0qBd0a_3pQ4&hl=da

[partofme]

I'm must say I'm happy we have astronauts fixing Hubble right now and I hope everything goes according to plan. It's something that has been in the works for a while but things various things kept putting it off. I watched a episode of NOVA that went over what they are going to do and how difficult it is going to be and there is a good chance something could go wrong.

[Dominick]

:eek:

What the heck are these? :ummm:
Gas :)
They're regions of interstellar gas in the process of contracting into stellar systems. Creation is a ever ongoing event out there :eek:

[Dominick]

I'm must say I'm happy we have astronauts fixing Hubble right now and I hope everything goes according to plan. It's something that has been in the works for a while but things various things kept putting it off. I watched a episode of NOVA that went over what they are going to do and how difficult it is going to be and there is a good chance something could go wrong.
Yes, Hubble should stay operational as long as possible. What's Obama's position on NASA funding by the way?

[Michael]

Gas :)
They're regions of interstellar gas in the process of contracting into stellar systems. Creation is a ever ongoing event out there :eek:

Wow! :eek:

I suppose I always understood the concept that the universe was still 'growing' but I never quite grasped the concept like that galactic-scale cloud thing happening out there right now (give or take a few million light-years or whatever).

I'm suprised Star Trek never showed new galaxies being born as they flew by... those would make great background scenes for the Enterprise to go crusing by (with Scotty appropriately traumatized in the engine room about the poor dylithium crystals!). :rofl:

[partofme]

Yes, Hubble should stay operational as long as possible. What's Obama's position on NASA funding by the way?

I know there is quite a bit of talk out of the administration about funding science but I'm honestly not sure regarding NASA specifically.

[Dominick]

Wow! :eek:

I suppose I always understood the concept that the universe was still 'growing' but I never quite grasped the concept like that galactic-scale cloud thing happening out there right now (give or take a few million light-years or whatever).
It's quite the party out there in the universe. Stars in all stages of development, galaxies colliding with each other, neutron stars spinning around their axis in less than a second, quasars putting more energy out in a second than our entire galaxy in a year, and there's black holes. Obviously one can't see those but their effects are obvious. The jet stream that emanates (ok, ok, is theoretically assumed to emanate) from the supermassive black hole in the picture below is 13,000 lightyears long. For reference, the Milky way has a diameter of 100,000 ly.

[Dominick]

Colliding galaxies, all Hubble pics.

[Donkey]

I'm must say I'm happy we have astronauts fixing Hubble right now and I hope everything goes according to plan. It's something that has been in the works for a while but things various things kept putting it off. I watched a episode of NOVA that went over what they are going to do and how difficult it is going to be and there is a good chance something could go wrong.
Speaking of fixing Hubble....

http://blogs.discovermagazine.com/badastronomy/2009/05/15/check-this-out-amazing-photo-of-the-sun/

[partofme]

Speaking of fixing Hubble....

http://blogs.discovermagazine.com/badastronomy/2009/05/15/check-this-out-amazing-photo-of-the-sun/

That's pretty awesome.

[Donkey]

That's pretty awesome.
Speakeasy hooked me up with that.

[partofme]

Speakeasy hooked me up with that.

Yeah I saw it in the random post thread and put it up on my Facebook.

[Donkey]

Yeah I saw it in the random post thread and put it up on my Facebook.
Lol!

I did the exact same thing.

[Dominick]

Meanwhile out there in space the Hubble has been succesfully maintained and the ESA satellites are unhamperedly moving toward their final destination which is an orbit around the second Lagrange point:

http://www.discussionworldforum.com/icons/lagrange2.gif

Lagrange points are those points in a three body system where the mutual gravitational fields cancel out and are therefore the ideal place for the third body to be "at rest" towards the other two.

[Michael]

:popcorn:

Excellent thread Dominick... I really appreciate your brief explanations! :)

Please feel free to continue your astral lecture series...

[Dominick]

:popcorn:

Excellent thread Dominick... I really appreciate your brief explanations! :)

Please feel free to continue your astral lecture series...
To make it even more interesting for you I'm going to offer a philosophical tangent on the issue. 'Existence' is a subject of philosophy after all, is it not ?

There's something about the 'pillars' in post #6 : They're 7,000 lightyears away so the image we're receiving now started its journey in 5,000 BC. There is some evidence that during that time these pillars were destroyed by a supernova, i.e. an exploded star. The evidence is not conclusive but for the sake of this argument, let's assume it is. Now the question is: Do these pillars exist ?

[Michael]

Now the question is: Do these pillars exist ?
Sounds exactly a slight variation on the old 'tree in the forest' question with a new time-dimension twist. :D

I like it - though I'm not quite prepared yet to offer a substantive reply. You can expect one though! ;)

[Michael]

There's something about the 'pillars' in post #6 : They're 7,000 lightyears away so the image we're receiving now started its journey in 5,000 BC. There is some evidence that during that time these pillars were destroyed by a supernova, i.e. an exploded star. The evidence is not conclusive but for the sake of this argument, let's assume it is. Now the question is: Do these pillars exist ?

The answer is apparently unknown. :D

However, I'll take your provision that the evidence for the supernova is conclusive and base my reply on that.

On that basis, one has to conclude, to the best of our human abilities to discern, that the pillars are no longer in existence at this time.

That being said, given the limitations upon our claims of knowledge of the supernova-caused destruction are exactly the same as the limitations upon our claim of knowledge of the existence of the pillars, as human beings, we really can't be absolutely certain whether the pillars do exist or not - even in the first instance without the evidence of the 'alleged' supernova.

The one angle that does present interesting possibilities is the definition "at this time" which of course is relative to human awareness, which is based on what we can observe at this time.

[Dominick]

The answer is apparently unknown. :D
You researched it ? I'm disappointed.


However, I'll take your provision that the evidence for the supernova is conclusive and base my reply on that.

On that basis, one has to conclude, to the best of our human abilities to discern, that the pillars are no longer in existence at this time.

That being said, given the limitations upon our claims of knowledge of the supernova-caused destruction are exactly the same as the limitations upon our claim of knowledge of the existence of the pillars, as human beings, we really can't be absolutely certain whether the pillars do exist or not - even in the first instance without the evidence of the 'alleged' supernova.

The one angle that does present interesting possibilities is the definition "at this time" which of course is relative to human awareness, which is based on what we can observe at this time.
No.
The answer is that they exist for us for another 1,000 years but not for themselves. Space and time have been discovered as relative concepts for 104 years now. Whatever is in the outward direction of the lightcone of a spacetime event is aware of the existence of that event. Only when the information of the subsequent event (originating locally in the Eagle Nebula) of the destruction reaches the Earth is it meaningful to speak of the absence of existence for the foregoing event. This is not semantics, this is the essence of the fabric of spacetime. If information (in the utterly broadest meaning of the term it has in science) were instant among arbitrary distances, the universe would not exist because it would collapse back into a singularity. This can and has been proven.
Time, and thus the duration of existence, are relative to the observer. My point is of course, as you might have anticipated, that philosophy completely ignores this and other aspects of contemporary knowledge.

[Michael]

You researched it ? I'm disappointed.
Don't be silly. That was my real answer according to the facts given and my long established epistemological position. I already noted the 'tree in the forest' problem of human claim of knowledge.

Besides, why on earth would I look up some 'science-stuff' to use in an argument against you? That's a waste of my valuable time. ;)

No.
:yoda:

:lightsabers:

The answer is that they exist for us for another 1,000 years but not for themselves. Space and time have been discovered as relative concepts for 104 years now. Whatever is in the outward direction of the lightcone of a spacetime event is aware of the existence of that event. Only when the information of the subsequent event (originating locally in the Eagle Nebula) of the destruction reaches the Earth is it meaningful to speak of the absence of existence for the foregoing event. This is not semantics, this is the essence of the fabric of spacetime. If information (in the utterly broadest meaning of the term it has in science) were instant among arbitrary distances, the universe would not exist because it would collapse back into a singularity. This can and has been proven.

I take it you mean 'proven, to the best of our scientific knowledge, at this time'. If so, then yes, that's the answer.

As long as you acknowledge that limitation of human falibility, then you can make all the claims that science can justify. Without it, no claim of knowledge can be rationally justified (IMHO!).

Time, and thus the duration of existence, are relative to the observer.

Yes, time and duration of existence are relative to the observer.

That is an integral component of my argument. All human knowledge is relative to the observer. I don't need Einstein's equations to 'prove' that to my own satisfaction. Rational philosophy supplies that conclusion - and long before Einstein came along.

My point is of course, as you might have anticipated, that philosophy completely ignores this and other aspects of contemporary knowledge.

I agree that the splitting of 'natural philosophy' into the three components of 'religion, philosophy and science' has been ugly. Unfortunately, it is a fact of human history and cannot be undone.

On that note, I think Stephen Hawking's Brief History of Time is an excellent move in that direction, but like all the academic disciplines over the last few decades, specialization has become endemic, making cross-disciplinary studies increasingly difficult if not impossible.

[Dominick]

I take it you mean 'proven, to the best of our scientific knowledge, at this time'. If so, then yes, that's the answer.

As long as you acknowledge that limitation of human falibility, then you can make all the claims that science can justify. Without it, no claim of knowledge can be rationally justified (IMHO!).
Ah, waving the magic wand again that attempts to make all knowledge look like it's something out of a tinfoil hat capped brain. ;)


Yes, time and duration of existence are relative to the observer.

That is an integral component of my argument. All human knowledge is relative to the observer. I don't need Einstein's equations to 'prove' that to my own satisfaction. Rational philosophy supplies that conclusion - and long before Einstein came along.
The term relative in this context has nothing whatsoever to do with human subjectivity. Neither the relativity towards nor the nature of the observer need to be vis-à-vis humans respectively human. It's relative for clocks, photons, energy or light too, in the exact same degree. In fact, it's relative for anything.

You take two clocks, synchronize them, put one at rest on your table, and send the other one around the Earth in the Space Shuttle and when they're brought back together they will show a difference that can be exactly predicted. In this specific case that difference will be so small that no human would be capable of sensing it.

And thus you or anyone else most certainly do need Einstein's equations to realize this. No philosopher ever has even hinted at this. Descartes or Pascal would both be entirely flabbergasted if they learned about it. I've never read anything from any philosopher that isn't based in Newton's static universe.


I agree that the splitting of 'natural philosophy' into the three components of 'religion, philosophy and science' has been ugly. Unfortunately, it is a fact of human history and cannot be undone.
That's not the problem I'm hinting at. The problem is that philosophy is deadlocked in the past and doesn't address recent knowledge, quantum physics even less than relativity. It's a wholly different ballgame out there today than when Descartes, Rousseau or even Nietzsche were alive. I'll continue to call it scholasticism until I read a contemporary philosopher that does address and incorporate that. :)


On that note, I think Stephen Hawking's Brief History of Time is an excellent move in that direction, but like all the academic disciplines over the last few decades, specialization has become endemic, making cross-disciplinary studies increasingly difficult if not impossible.
aBHoT may be attractive to non-scientists, it's poor scientifically. There are much better ones around.

[Michael]

Ah, waving the magic wand again that attempts to make all knowledge look like it's something out of a tinfoil hat capped brain. ;)
It is the same rationally consistent epistemological position that I've been asserting for the last half-dozen years in discussions with you.

Where you got the fetish for absolutism is beyond me. And make no mistake - your argument is all about killing science and turning it into a religion with high priests and approved doctrine. That's where your epistemology leads to - you are claiming the role of God's truth for science (or math).

The conception of epistemology that I've put forward is the ONLY ONE that can be used to rationally recognize claims of knowledge by science AND also can be used to rationally deliniate the realm of God and faith.

Why that annoys you is beyond me trying to figure out.

First rule of philosophy. Don't start with the answer to the question!

The term relative in this context has nothing whatsoever to do with human subjectivity. Neither the relativity towards nor the nature of the observer need to be vis-à-vis humans respectively human. It's relative for clocks, photons, energy or light too, in the exact same degree. In fact, it's relative for anything.
If it is relative for anything and everything, that means it is relative for human claims of knowledge and that is the essential core of my epistemological position here. And if everything is relative to humans, everything is relative to anything and everything by definition.

Humans are the key to the equation, knowledge cannot be abstracted outside of that human context. And that human context has flaws, limitations, perceptions, egos, sex-drives and silly passions - thus it is always inherently and ultimately suspect.

You take two clocks, synchronize them, put one at rest on your table, and send the other one around the Earth in the Space Shuttle and when they're brought back together they will show a difference that can be exactly predicted. In this specific case that difference will be so small that no human would be capable of sensing it.

And thus you or anyone else most certainly do need Einstein's equations to realize this. No philosopher ever has even hinted at this. Descartes or Pascal would both be entirely flabbergasted if they learned about it. I've never read anything from any philosopher that isn't based in Newton's static universe.

1. I believe Descartes or Pascal would both be entirely flabbergasted by the concept of machines flying around the planet and machines that make measurements of time increments too small for human conception to even bother with the significance of the time differential (however brilliant these two fellows might be).

2. How can Plato's philosophy be described as based on Newton's universe - static or otherwise? There's a bit of a chronology problem there.

3. Philosophy is predicated upon pure thought. Why should pure thought have to pander to your own favorite facts? Isn't that a bit idealistic or egotistical on your part?

That's not the problem I'm hinting at. The problem is that philosophy is deadlocked in the past and doesn't address recent knowledge, quantum physics even less than relativity. It's a wholly different ballgame out there today than when Descartes, Rousseau or even Nietzsche were alive. I'll continue to call it scholasticism until I read a contemporary philosopher that does address and incorporate that. :)

I'll call it "faith" if/when some philosopher starts to base his thoughts on any given contemporary scientific theory as the starting point of thought.

aBHoT may be attractive to non-scientists, it's poor scientifically. There are much better ones around.
Of course there are better ones around - the ones that pander entirely to the scientific system. But they are mostly unaccessible to those who haven't invested a dozen years of study in order to read it.

Likewise with philosophy - most of it is unaccessible to non-philosophers without a dozen years of study in order to read it.

This is the problem of specialization. Advanced knowledge requires advanced education and that requires substantial investments of time for each individual in order to pursue it. Cross-disciplinary studies, by definition, implies limits on the complexity of information supplied by each discipline.

[Donkey]

The pillars don't exist. If we accept that they were destroyed sometime in the past then we have to accept that they do not exist today. It doesn't matter how long it takes for the broadcast to get here. The pooch is screwed. If we were to visit in person, it would not matter how fast we were to get there, including instantaneous transportation, unless we broke into backward time travel, we would never be able to visit these pillars because they are gone.

If I may draw an analogy, I see the image which we perceive much as a last will and testament of a deceased person. Simply because an executor reads the will out doesn't mean that the person is still alive. Time, space and light are the executors of these pillars.

[Michael]

The pillars don't exist. If we accept that they were destroyed sometime in the past then we have to accept that they do not exist today. It doesn't matter how long it takes for the broadcast to get here. The pooch is screwed. If we were to visit in person, it would not matter how fast we were to get there, including instantaneous transportation, unless we broke into backward time travel, we would never be able to visit these pillars because they are gone.

If I may draw an analogy, I see the image which we perceive much as a last will and testament of a deceased person. Simply because an executor reads the will out doesn't mean that the person is still alive. Time, space and light are the executors of these pillars.
Excellent analogy Donkey. :)