<p>Very large baseline radio telescopes bring many mysteries of the cosmos to us. We build them because they are feasible.</p>
<p>Say, in the future, we could build very large optical telescopes in deep space, either with physically large mirrors, or via breakthroughs in interferometry, to get diameters or at least <em>effective apertures</em> in the order of a few to tens of kilometers.</p>
<p>Would this bring us fundamentally new knowledge of the cosmos or merely pretty pictures, say of the flares on distant suns, that are incremental advances to our understanding?</p>

CC BY-SA 4.0
2021-12-09T21:56:04.640Z
Can you clarify how much larger than the under construction ~30 meter ground-based telescopes such as TMT, GMT, E-ELT or proposed 8-15 m sized space telescopes e.g. [LUVOIR](https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infrared_Surveyor) you're thinking of?
astrosnapper
CC BY-SA 4.0
2021-12-09T22:11:56.750Z
Hi, sure. In the question I mention mirror sizes of 10s of km. It is interesting in itself that you ask for a size. This implies to me you have an idea of interesting fundamental results that could be obtained if the size is > x. Can you elaborate? Thanks.
Dipti
CC BY-SA 4.0
2021-12-10T00:58:19.343Z
We won't know until we build them, so I would say this is opinion based.  Science is partly a gamble - you're hoping every shot in the dark hits something.  Some shots are estimates, some are educated guesses but many are looking because you don't know what you'll see and that's worked well for humanity overall.
StephenG - Help Ukraine
CC BY-SA 4.0
2021-12-10T01:21:45.387Z
I hope we have at least some guesses as to what we'll find. I'm sure there are hypotheses and gaps in our knowledge that could be filled by visual observations, say by measuring fine details on the surface of a neutron star, for example. Or by observing fine details on the edge of a black hole's horizon.
Dipti
CC BY-SA 4.0
2021-12-10T08:52:12.907Z
@MissyStice sure. That's all the prosa one writes into grant applications. But whether that will be found or not - is to be seen. And whether the forseen new knowledge is 'fundamental' is even more up to judgement. Fundamentally new things cannot be planned for - they are the unknown unknowns.
planetmaker
<observational-astronomy><telescope><cosmology><space-telescope>
What new fundamental knowledge could a very, very large optical telescope bring?
Dipti
# What new fundamental knowledge could a very, very large optical telescope bring?

(Asked by: username_0 on 2021-12-09)

Very large baseline radio telescopes bring many mysteries of the cosmos to us. We build them because they are feasible.

Say, in the future, we could build very large optical telescopes in deep space, either with physically large mirrors, or via breakthroughs in interferometry, to get diameters or at least *effective apertures* in the order of a few to tens of kilometers.

Would this bring us fundamentally new knowledge of the cosmos or merely pretty pictures, say of the flares on distant suns, that are incremental advances to our understanding?

**Tags:** observational-astronomy, telescope, cosmology, space-telescope

> **Comments:**
> **username_1**: Can you clarify how much larger than the under construction ~30 meter ground-based telescopes such as TMT, GMT, E-ELT or proposed 8-15 m sized space telescopes e.g. [LUVOIR](https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infrared_Surveyor) you're thinking of?  
> **username_0**: Hi, sure. In the question I mention mirror sizes of 10s of km. It is interesting in itself that you ask for a size. This implies to me you have an idea of interesting fundamental results that could be obtained if the size is > x. Can you elaborate? Thanks.  
> **username_2**: We won't know until we build them, so I would say this is opinion based.  Science is partly a gamble - you're hoping every shot in the dark hits something.  Some shots are estimates, some are educated guesses but many are looking because you don't know what you'll see and that's worked well for humanity overall.  
> **username_0**: I hope we have at least some guesses as to what we'll find. I'm sure there are hypotheses and gaps in our knowledge that could be filled by visual observations, say by measuring fine details on the surface of a neutron star, for example. Or by observing fine details on the edge of a black hole's horizon.  
> **username_3**: @MissyStice sure. That's all the prosa one writes into grant applications. But whether that will be found or not - is to be seen. And whether the forseen new knowledge is 'fundamental' is even more up to judgement. Fundamentally new things cannot be planned for - they are the unknown unknowns.  

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## 0 answers

