Comment Re:Fear Mongers Didn't Want to Let Cassini Fly (Score 1) 45
That is one advantage of using the SLS for the Europa-clipper - it would be a Hohmann trajectory, with no subsequent Earth-flybys to get people anxious.
That is one advantage of using the SLS for the Europa-clipper - it would be a Hohmann trajectory, with no subsequent Earth-flybys to get people anxious.
Viking, Voyager, Galileo, Cassini - these were the so called "Flagship" missions - big, envelope-pushing missions intended to substantially advance our knowledge of the solar system. (MSL is really another, but Mars is special for NASA and so they don't call it that.) They have somewhat fallen out of favor, as they are very expensive and prone to delays and overruns, but it is hard to see how there can be substantial advances, particularly in the outer solar system, without them.
The next mission of this class will, Congress willing, be the Europa-clipper, which is slowly getting to the AO stage. I can hardly wait.
What is wrong with these people? Are they unaware that such has been proposed time and again by past luminaries?.
Nothing is wrong with them , as they still get rewarded for making bad predictions.
No-one ever lost money betting against an A.I. prognosticator.
That depends. How often do you get fired?
At a minimum, at least as often as you get fired.
Having read the article, I think that "With a Bang" sort of waffled on this. It is hard to see how SuperMassive Black holes (SMB) form in the time available for them to form. (There is a large literature on this, but basically there are problems of the seeds - are the seeds Pop III stars, or something more exotic - and time - how can the mass move around enough to form SMB by z ~ 6?).
I don't really feel you can safely answer the "which came first" question until you know how the SMB actually formed.
A one hour video lecture, Supermassive Black Holes and the Problem of Galaxy Formation, might be interesting to people interested in these problems, but it deals with the galaxy problem more than the SMB problem.
Of course, as the "With a Bang" article points out, if you are willing to wait and not have everything be simultaneous, you can have both large scale structure formation and small scale structure formation going on simultaneously, with the small scale going to completion earlier, and both together yielding what we see today.
Why is the answer always assumed to be binary? Both processes could have been occuring simultaneously.
I am sure both were occuring simultaneously, the question is, which dominates? The two sets of processes have different time constants (growth rates), arising from different physics. For both to be more-or-less equally powerful requires these time constants to be more-or-less matched, and that seems improbable and fails "Occam's razor" type "tests."
So, could be, but don't expect that idea to gain traction, at least without a good theory as to why things should be that way.
we first expected and then found supermassive black holes at the centers of practically all large galaxies.
"expected" is sure not how I remember it, and in fact I think this has the historical record backwards. Quasars were definitely a surprise, and the Super Massive Black hole (SMB) interpretation of quasars took a while (a decade at least) to catch on, and the consensus that most galaxies have a central SMB came after that, after some local galaxies (such as our own) showed signs of having a SMB too. Before all of this most astronomers weren't interested in black holes and even the small number of General Relativity types (such as Zeldovich) who were, and who were looking them, were looking for stellar mass sized black holes, not the SMB variety.
All in all, I think it would be more accurate to say that the SMB-galaxy connection was forced upon astronomers by the data, rather than that they expected it.
A bug in the mosaic screensaver caused downloaded images to remain uncached.
I have to wonder about that.
The OP did 79.61 GB in one day, which works out to 7 Mbps over 24 hours. That seems like a lot of images (several a second?) for a screen-saver to download.
A better analog might be, suppose someone said in testimony
I buried all my documents in a box out in the desert.
Could they then be compelled to provide the location if police searches turned up a blank? Seems like they could.
Of course, if you are willing to go to jail and wait it out, the "compulsion" is never forever, Seems like that might depend on just what's in those documents.
You do not have to participate in the opening of your safe. A locksmith or torch can do that without you.
Your encrypted documents, on the other hand, may not be crackable without your help.
Note that courts seem to feel that Iris-scans, fingerprints, etc., are not "testimony," and so are not protected. That's something to keep in mind if you wanted to purely rely on biometric keys for your encryption.
IANAL, and this is not legal advice.
Building three unfathomably massive anti-tornado walls would count as the infrastructure project of the decade, if not the century. It would be also be exceedingly expensive.
If it is not exceedingly expensive, it's not the infrastructure project of the century.
Franson's theory cannot be right, as it disagrees with the solar system tests of General Relativity
His Equation 18 predicts a change in the gravitational red shift by a factor of 9 alpha / 64 for photons, where alpha is the fine structure constant (~ 1/137), so the correction is ~ 1.08 x 10^-2. The gravitational red shift has been tested, by GPS and also by Gravity Probe A, with an accuracy of a few parts in 10^-4 (see Figure 3 in that reference). This excludes the Franson correction, and so his theory cannot be correct. Since the Shapiro delay also depends on the gravitational redshift, Franson's theory thus predicts a 1% change in that too, which is also much too large to be consistent with experiment (see Figure 5), again excluding the Franson theory.
So the theory is wrong, and the other problems I have with the paper are irrelevant.
The moon is made of green cheese. -- John Heywood