Beyond that and I just lose control of it all. Besides, If I keep it in the Milky Way, I can stick to Newtonian mechanics, which I understand well enough. I took all the undergraduate coursework offered in modern physics (relativity and the quantum) and I could work the problems in the book, but I could never get a grip on what was actually going on.

It has been said that when Newton published his principia mathematica, there were only a handful of people that could understand it. But now many do.

WAY back in the early 2000′s I worked on a laser guide star for the Keck observatory in Hawaii…
Adaptive optics allows ground based telescopes to operate near their diffraction limit, but with some pretty important caveats…

FIRST you need a bright ‘reference star’ to be very near (within a few arcseconds) the target you want to observe… you measure the light from the reference star and see how the atmosphere has distorted it, and then you apply a complementary distortion to a deformable mirror to undo that distortion. (When I say a ‘bright reference star’ ‘bright’ is brighter than around 10th or 11th magnitude) This limits you to maybe ~1% of the sky if you are only using natural stars.

SECOND you can only really correct in the infrared wavelengths- the reasons for this are complicated and would take a lot of writing to cover, but it boils down to this: The atmospheric turbulence impacts shorter wavelengths more, if you want your adaptive optics system to correct the light at shorter wavelengths then you need to have a brighter reference star…. Stars bright enough to allow correction at visible wavelengths are so few that its not worth the trouble…

The laser guide star let us get around the first restriction, allowing us to create an artificial star anywhere we want in the sky to use as a reference, but it did nothing to get us around the second restriction…. the laser guide star works by making the sodium atoms in the upper atmosphere glow where the beam hits them, but the resulting star if faint- at BEST 8th magnitude, more typically 10th. There are only so many sodium atoms up there, so turning the laser power up wont make the ‘star’ any brighter. So the 10 meter diameter Keck telescope, with the laser guide star, could have better resolution than the Hubble – but only in the infrared- In the visible wavelengths Hubble was the champion.

By losing out on the visible portion of the spectrum you are not just losing out on the information that might be contained in those wavelengths, you are also losing out on the resolution you could have with shorter wavelengths. The resolution of a telescope (in Radians) is proportional to the wavelength divided by the telescope diameter. The smaller the wavelength, the smaller the features a given telescope can resolve. A 10meter diffraction limited telescope at 500nm wavelength has 6 times better resolution than one viewing at a wavelength of 3000nm.

If you could create BRIGHT guide stars in the sky (and here I am talking comparable to the brightest stars in the sky- 0th-2nd magnitude) where you wanted, then you could do adaptive optics compensation at much shorter wavelengths… and that capability is exactly what is being worked on now. It does not take a very powerful laser in space to create a ‘star’ as viewed from the ground that is as bright as the brightest star in the sky even at a distance of 200,000 km…

Who knows when or if we will ever be able to build a 30m or 100m diameter space telescope, but astronomers are currently building 30m telescopes on the ground with planning underway for even larger… if they could operate at their true diffraction limit AND DO SO AT SHORT WAVELENGTHS then the resolution they would have would be revolutionary.

Space telescopes will still have some advantages, of course… so they will play a valuable role in astronomy, but getting the diffraction limit with huge ground telescopes will lead to incredible advances!

The other pictures were taken in a large room next to that cleanroom – I had to walk through that room to get to yet another cleanroom for another project. I made sure that taking pictures was allowed before doing so…. as you might imagine there was a full-time guard put on it to make sure no one unauthorized got too close.

Security precautions were pretty high, given its cost.

And it’s not exactly street legal...

The sort of questions physicists deal with now are so counter-intuitive and abstract that they are only accessible through impenetrable mathematics. At best, they simply cannot be understood by those who have not mastered the math; at worst, they may simply be beyond human capacity to understand at all.

Most here are not on Facebook but I’d like to invite you to a group I started called “Scientists Smoking Weed”.
You can create an anonymous account to keep your anonymity but I will be giving up mine. So be it.

The group tracks the bizarre theories scientists are frequently coming up with to explain the unknown. “Bizarre” because most layman can’t understand them. Not all posts are serious. Some members are stoners I don’t even know.

It may simply not make any sense to ask the size of the universe, just as it makes no sense to ask what was there before the universe happened, or what is beyond the edge of the cosmos. These statements are linguistically correct, but may have no physical referent. The sort of questions physicists deal with now are so counter-intuitive and abstract that they are only accessible through impenetrable mathematics. At best, they simply cannot be understood by those who have not mastered the math; at worst, they may simply be beyond human capacity to understand at all. How can we think of science as an objective pursuit when it is so intimately entangled with the concepts of perception and consciousness? We all experience the universe we perceive, not the one that actually exists.

On the other hand, whatever the universe REALLY is, we can only deal with the parts we can make sense of. So our minds construct models and shortcuts that allow us to function and survive regardless of what is actually going on “out there”. In other words, we can’t understand the real universe, so we have to devise one that we CAN understand in order just to get along. This universe, our internal model, is the one we have to deal with on a day-to-day basis, so it is (for all practical purposes) just as real and important as actual reality.

I’ve been getting into the Tokyo Olympics on the telly, and I enjoy watching, and highly admire, the skill and dedication of the athletes. These kids are doing remarkable things with their bodies, completely without any true understanding whatsoever of the physical dynamics of motion in a gravitational field or of the molecular biology of the human body. They simply do not need to know what is going on at the space-time or quantum levels. Likewise, we don’t need to understand (or maybe we just can’t) what is happening at cosmological scales. Our minds are still capable of coming up with the strategies we need to deal with it. Not only do we know what what we need to know, we decide just what it is we need to know.

At the risk of going all Zen on you, remember: You don’t have to be black or Christian to enjoy Gospel music.