David’s Comments (group member since Dec 13, 2009)

David’s comments from the Science and Inquiry group.

Kirsten wrote: "http://www.space.com/scienceastronomy...

I was reading on Twitter (a great source, I know, don't judge) that they are finding proof of other univer..."

Kirsten, it's possible, it's also a cool idea, but that's about far as it goes. As mentioned in the excellent article that you quoted, there is no evidence that multiple universes exist, and there might never be a way to prove or to disprove the idea. As the article mentions, the idea is a counter-argument against the so-called "anthropic principle", that the universe has been fine-tuned so that life on Earth could thrive. If there are multiple universes, each with a different set of fundamental physical constants, then we just happen to have grown in one of the (minority of) universes that is favorable toward life.

Kirsten wrote: "I'm working on How the Mind Works and eying one of Brian Greene's books."

Kirsten, how do you like "How the Mind Works"? (I plan to read it real soon.)

Alex wrote: "Theoretically, we have apparently invented teleportation. Or something. This frankly doesn't seem like a good idea."

Thanks for the link to the article, Alex. Quite interesting! Reading the article carefully, I think that it means that the technology may be able to give the illusion of teleportation by the use of cloaking, rather than to perform actual teleportation.

tana wrote: "Temple Grandin's books "Animals make us human" and "Animals in translation" are also very interesting."

I really enjoyed "Animals in Translation". Quite an interesting point of view.

Matt wrote: "I am new here so I am not sure if this has been nominated before but how about "From Eternity to Here" by Sean Carroll?"

Matt, it's late to nominate the book for January. Toward the end of December, nominations will be open for the February book of the month. Be sure to nominate it then!

Matt wrote: "I bought this book about 2 years ago and I have read it on and off. I was wondering if anyone else was reading it or would like to work out some of the problems with me."

Matt,
I have also been going through the book, very slowly. I read some, set it aside, and then come back to it later. I find that the book is so terse--it's almost like you really have to have studied the subjects before hand, before you can appreciate what Penrose has to say.

Matt wrote: "Hi, My name is Matthew. ...I am currently reading "From Eternity to Here" by Sean Carroll. Are any of you reading that one?

Welcome, Matt! I have not read "From Eternity to Here". The book looks interesting. Let us know how you like it. By the way, have you read Penrose's book "Cycles of Time"? Sort of on a similar subject.

I gave 5 stars to Absolutely Small: How Quantum Theory Explains Our Everyday World. I really appreciate how the book explains how quantum theory applies to everyday, "macroscopic" properties of molecules. Things you hear in the news everyday, like greenhouse gases, alcohol, cholesterol, partially hydrogenated fats, and more.

Who else is reading the book now?

Prashant wrote: "Has anyone read/ing Brighter than a Thousand Suns by Robert Jungk? ..."

Prashant, I have not read the book--but it looks fascinating.

The January 2011 poll is here:
http://www.goodreads.com/poll/list/11...

Eric, the equivalence of space and time was first proposed mathematically by Minkowski, and shortly after, put on a physics basis by Einstein. Einstein started with the basic postulate, that the speed of light in empty space is the same, regardless of one's frame of reference. From that postulate, he derived the theory of special relativity (it's just a matter of applying mathematics). The equivalence of space and time is often expressed mathematically with the Lorentz transformations, such as:
x' = (x-vt)/Sqrt[1-v2/c2]
t' = (t-vx/c2)/Sqrt[1-v2/c2]
So, asking for observational evidence that space and time are two sides of a coin, is equivalent to asking for evidence that the speed of light in a vacuum is invariant.

The most famous experiment on this subject was by Michelson and Morley in the late 19th century (for which they won a Nobel Prize). They showed that light traveled with the same speed in two different (perpendicular) directions. Kennedy and Thorndike generalized the experiment, and showed that even over a period of months, when presumably the earth was traveling in different directions, the speed of light was invariant.

Time dilation (the second of the two equations above) was directly measured by Rossi and Hall in 1941, using mu-mesons. These particles enter the earth's atmosphere from above (produced by cosmic rays) at nearly the speed of light. Rossi and Hall measured their rate of decay at the top of a mountain and at sea level; they found that the particles decayed much more slowly than expected, given the extra time needed to fall the extra 2000 meters from the mountain-top to sea level. So, this was a direct measurement of "time dilation".

There have been lots more experiments, but you might be performing one every day, without realizing it! Do you use a GPS unit? Its accuracy depends on the software built into it, that takes relativity into account! The GPS system must account for both special relativity and general relativity--if they were not taken into account, your GPS unit would drift by 10 kilometers each day!

Middle East?

Is anybody else reading Death from the Skies!: These Are the Ways the World Will End . . .? I enjoyed the book very much. I really appreciated how the author evaluates the probabilities of various events. For example, an asteroid or comet collision is the most probable disaster--but also the easiest disaster to prevent, given enough warning time. The author admits that some other scenarios are very unlikely--but he includes them anyway, because they are fun to read about.

I thought that the linking of cycles (64 million years) of biodiversity with oscillations of the solar system perpendicular to the plane of the galaxy was novel, and thought-provoking.

I also enjoyed reading about the scenario of an alien invasion. It's not what you think, so I don't want to give away the scenario as a spoiler--you have to read it!

Jayme wrote: "Is this where the discussion for both books will take place? Sorry, but I didn't see any other threads that looked right and I'm kinda new here."

Yes, Jayme. Discuss both books here.

Yes, Alex; The Grand Design is on my "to read" list. Whether or not the Science and Inquiry group votes to read it, I will be starting on the book before too long.

I also enjoyed Sagan's response to the question, whether he thinks that science will ever demonstrate the existence of God. Sagan answered that it depends on one's definition. He considered two opposite poles in the definition of God. On one pole, there is the god of Einstein and Spinoza, that is, god is a single set of physical laws. And of course, according to that definition, Sagan is a believer; the laws have domain over the entire universe.

The opposite pole is a guy with a long white beard who sits on a throne in heaven and observes everything. With that definition of a god, Sagan doubts science will ever provide tangible evidence.

I believe that the question, as stated, could be interpreted as a distance or a time. Either way. If you do a Google search for the words universe end, you will get results from both points of view.

In fact, there is a third interpretation--probably not intended, but yet equally valid; "is there an end in space-time coordinates?" In this third interpretation, distance and time are equivalent. Imagine a light cone that started expanding at the time of the Big Bang. The question becomes, what is beyond the edge of the light cone?

Alex wrote: "I've read Sagan's book and would love to discuss it with anyone who's reading it. ..."

Alex, I really enjoyed Sagan's concept of "God of the gaps." That is, when an explanation of some natural phenomenon is not known, it is "a gap", and therefore it is attributed to God. As scientific progress is made, many of the gaps get filled in by rational explanations. There are very few large gaps left. One of the last great gaps is the origin of life. And Sagan shows that a lot of progress has recently been made in filling in that gap.

It looks like Absolutely Small: How Quantum Theory Explains Our Everyday World is the winner. It will be our December Book Club selection. I'm really looking forward to reading it!

The two books for November are both great. Is anybody else reading either of the books?

The Varieties of Scientific Experience: A Personal View of the Search for God
Death from the Skies!: These Are the Ways the World Will End . . .

Thanks, everyone! Nominations are now closed. You can vote for your choice from these five excellent books:
http://www.goodreads.com/poll/show/40...