Slashdot Mirror
Ask The Bad Astronomer
Astronomer, author, columnist, and successful populizer of science Phil Plait, perhaps best known as The Bad Astronomer, is a regular sight on Slashdot for his unusual ability to find lucid explanations of esoteric scientific claims and controversies. Phil has graciously agreed to answer Slashdot readers' questions, so ask him below about space, science, debunking conspiracy claims, and anything else that makes sense. Asking more than one question is fine (and encouraged!), but please separate unrelated questions into separate posts, lest your questions be moderated down.
You've been doing The Bad Astronomer thing for a while. How come you haven't become a better astronomer by now?
"I use a Mac because I'm just better than you are."
What is the universe expanding into?
Which do you find more annoying.
Star Trek which can spend a good portion of the show trying to explain how and why they break the laws of physics.
or
Star Wars which breaks the laws of physics but doesn't care to explain themselves.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
There are a large number of light pollution articles to be found on the Sky and Telescope website. We amateur astronomers are keenly aware that light pollution isn't just about being able to see more stars from our backyard. Yet, when I mention the subject to friends, family, co-workers, etc, I often get a blank stare. "What's 'light pollution'?" What do you think can/should be done to improve widespread public awareness of light pollution and its effects?
The cake is a lie.
If you could give Apollo-level funding to a single NASA program, what would it be? Would you direct that money internally or involve private space companies?
Finally, what do you think of lunar-based observatories from a cost vs. performance standpoint?
"I zero-index my hamsters" - Willtor (147206)
Given your unique position, I'd like to know your answer to this question:
What do you think is the currently a bigger threat to legitimate science:
- The growing wave of anti-intellectualism and anti-science that seemingly rejects science outright on certain issues
- Or the growing wave of pseudo-science that undercuts science by adopting the trappings of science but none of its procedures?
Thank you for your time.
"Enough of this wretched, whining monkey life." -- Marcus Aurelius, _Meditations_, Book 9, 37
How serious is the amount of 'space junk' orbiting Earth? Will it have a substantial impact on the future of space flight, manned or otherwise? What are some of the best (or at least most innovative) ideas you've heard about for deorbiting big junk or cleaning up smaller bits of debris?
This has been a test. If this had been an actual Sig, you would have been amused.
Those shows should ABSOLUTELY exist - and they should be dedicated to debunking them as completely and unassailably as possible.
Spend the first third of the show explaining the myth; spend the next 2 thirds ripping it to pieces.
DG
Want to learn about race cars? Read my Book
Actually, we have, but we all decided that it would be best not to let you in on it.
Changa hates change.
Whenever I research this, I come back to the "galactic rotation problem" as the most solid evidence.
That isn't the most solid evidence. It was just the first evidence, and if it was the only evidence then Dark Matter would not be preferred over the idea of a modified gravitational theory. Since then there have been two major additional forms of evidence for dark matter. The first is gravitational lensing.
According to General Relativity, mass bends bends light that passes by it. We have measured this effect before with objects of known mass, and the predictions of GR are dead on. Astronomers have looked at how strongly light is bent when passing by large galaxies, and used this to compute the mass of the galaxy. The numbers they get are much greater than the mass of the visible material, and more importantly match up very closely with the estimates of dark matter mass obtained by looking at rotational curves.
The most outstanding evidence of this is from the Bullet Cluster. Here two galaxies had passed through each other, and you can see how the different types of matter were slowed down by different amounts depending on how likely they were to collide. The gas clouds were slowed the most, and the large structures (stars, etc) slowed down less. But if you look at the gravitational lensing, you see that there is a big chunk of non-visible mass that was not slowed down by the collision at all. This is exactly what you would expect to see if the galaxies contained non-baryonic dark matter, and can't be explained by modified gravity at all.
The second major evidence is the cosmic microwave background radiation. I don't pretend to understand this, and thus won't try to expound, except to note that the ratio of baryonic matter to non-baryonic matter found using the CMBR also agrees with the dark matter estimates found using galaxy rotation curves and gravitational lensing.
So we have three drastically different ways of indirectly measuring the same thing, and they all come up with the same result. That is pretty strong evidence in my book.
How long do we have to put up with the notion of "Dark Matter"?
My guess is quite a long time, because it is almost certainly correct. Hopefully though, we will have direct evidence of dark matter with the next few decades, which should make it less annoying :)
If one views UFO's as a mystery instead of as "aliens", do you think there's a legitimate case for further study, even if it may only produce psychology lessons?
Reliable pilot and passenger witnesses have seen "flying disks" in broad daylight up close, for example. I'd like to know what triggered that perception if it's not "real".
Table-ized A.I.