Wonder what that looks like when you’re on a planet in the middle strand. Like our milkyway but each hemisphere of the sky has an additional oval milkyway in it. 
5 Likes
That HAS to have been created by Douglas Adams or Terry Pratchett. Essential reading for the bemused cosmic wanderer…
8 Likes
A quote from the preface,
" If we could analyze a galaxy in the laboratory,
we would deform it, shock it, probe it in order to discover its properties. The peculiarities of the galaxies pictured in this Atlas represent perturbations, deformations, and interactions which should enable us to analyze the nature of the real galaxies which we observe and which are too remote to experiment on directly"
The universe can now breathe a sigh of relief.
5 Likes
Halton Arp displays a disturbing set of priorities when his curiosity is piqued.
Be thankful he has never tried to get to know YOU.
“deform it, shock it, probe it”…
If you meet this guy at a conference, make your excuses, and leave.
6 Likes
7 Likes
I still don’t fully understand how they do the alignment, I think “just make the dots meet, job done”? 
I remember the part that they could not package it perfectly pre-aligned because they needed to fold it up. And I understand that alignment is mechanically fiddly — the mathematical part is what I’m missing.
Is the alignment hard because each mirror moves in three dimensions and around three axes and there are too many permutations?
4 Likes
One of the reports I saw said that the telescope not only had to be aligned, it also had to be collimated.
I can’t claim any first-hand knowledge of collimating telescopes, but I’ve done some in the field of gamma ray radiography, and it’s more of a black art than a precise science. Depending on the object you’re trying to image, and the distance, you may actually want some parts of the beam to be out of focus.
3 Likes
Short answer, yes. 
I was fascinated to learn that in order to get the focus good enough to see clearly 13 billion (in essence) light years away, the Webb has to use ultra-precise tensors to push and pull sections of each mirror so carefully that most photons from the source hit the optical imager at the same instant. Which is crazy precision, but you need a sharp image to see those extreme distances. As well as nearby things like exoplanets, which are also up for examination. I couldn’t believe we already saw exoplanets in a post above - Jupiter sized, but still! I expected it would take the JW to do that.
4 Likes
It’s got a lot to do with precision. These mirrors need to align insanely precise so they form an exact geometry, and as far as I know they have to align “together”, you can’t just drive one mirror into position and then the next, you only really see if they are properly aligned in conjunction with at least some other mirrors in the constellation. So the whole thing becomes “ok, these mirrors look good, now let’s do these. Ok, they’re good to each other, but the alignement with the others we did isn’t quite right, so let’s readjust those a bit more. Ok, here comes the next mirror, oy wey that looks good with those, but not with these, so we have to give the whole bunch another nudge” and so on and so forth…
6 Likes
All I can say is collimating a simple backyard telescope is complex enough. A seasoned pro can do it in a few minutes. A beginner can feel like they will never get it done. I cannot imagine aligning so many mirrors… 
4 Likes
SpaceNews: ESA suspends work with Russia on ExoMars mission.
4 Likes
That’s not just political, that’s also common sense… With the way things are going, it’s anybody’s guess if Roskosmos will be able to launch in september…
5 Likes
CNN: Tonight is Earth Hour. Here’s how you can participate.
1 Like
4 Likes
4 Likes
Twice today, I was outside working and heard what I swear was a meteor burning up in the atmosphere and yet, there are no active meteor showers right now, that I am aware of. Anyone know of anything happening?
It was really strange both times. Scared me both times because it is so quiet where I live. Did not see anything though because it took a few seconds for me to locate the direction of the sound and by then, it was over. Sure wish a chunk of meteor would land in my yard
Of course, it is also very possible it is an experimental aircraft. I know there is one that is supposed to avoid sonic boom. I live in a well used flight path for super sonic testing out of New Mexico. I have heard many sonic booms. The weather is very clear and excellent for flight testing
3 Likes
If it would have been big enough to make a sound audible on the surface, I’m pretty sure there would be some note of it. I have seen the one or other pretty big meteor burning up, none of which I heard.
3 Likes
I have heard them before while watching them and no mention of it. Since it was daytime and bright and sunny, I doubt anything would have been very visible. I feel lucky to have seen and heard the 2 that I encountered. It’s just the fact there is no meteor shower right now…it is odd. Especially since it happened twice. Still wish it had landed in my yard.
Then again, there was this in April
Look what I just found
8 Likes
