Book: The Four Percent Universe

Chad Orzel at Uncertain Principles reviews Richard Panek’s The Four Percent Universe. The subtitle is Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality.

It’s not a book about the known facts regarding the nature of the universe so much as a book about the process by which those facts were determined and became accepted.

Here’s a snippet from an interview with Panek on Amazon:

Q: Well, then, what do astronomers mean by “dark matter”?

Panek: A mysterious substance that comprises about 23 percent of the universe.

Q: And dark energy?

Panek: Something even more mysterious that comprises about 73 percent of the universe.

Q: Okay, 73 and 23 add up to 96 percent, which does leave a four percent universe. But if we don’t know what dark matter and dark energy are, how do we even know they’re there?

Panek: In the 1970s, astronomers observed that the motions of galaxies, including our own Milky Way, seem to be violating the universal law of gravitation. They’re spinning way too fast to survive more than a single rotation, yet we know that our galaxy has gone through dozens of rotations in its billions of years of life. Galaxies are living fast but not dying young—a fact that makes sense only if we say that there’s more matter out there, gravitationally holding galaxies and even clusters of galaxies together, than we can see. Astronomers call this substance dark matter.

Q: And the mysterious dark energy?

Panek: In the 1990s, two independent teams of astronomers set out to discover the fate of the universe. They knew the universe was born in a big bang and has been expanding ever since. Now they wanted to know how much the mutual gravitation among all this matter—dark or otherwise—was affecting the expansion of the universe. Enough to slow it down so that the universe would eventually grind to a halt, then collapse on itself? Or just enough that the expansion would grind to a halt and stay there? In 1998 the two teams came to the same conclusion: the expansion of the universe isn’t slowing down at all. In fact, it’s speeding up. And whatever force is counteracting gravity is what they call dark energy.


Neil DeGrasse Tyson puts Bill O’Reilly in his place

This is the source of a beautiful quote that I’ve seen going around the Web. Astrophysicist Neil DeGrasse Tyson explains what should be obvious, that science explains a lot of things that we thought were divine and we do know what causes tides.

The Big Gang at a glance

Cosmology from the Big Bang onwards

I must find the source of this picture! It was published recently and shows the expansion of the universe though various stages.

For Young-Earth Creationists–how to argue your position

Mike G. over at Spinoza’s Bicycle has some advice for YECs trying to argue that the Earth is a young creation: “What I Need.” Hint: it’s not a blanket assertion that conventional science is one vast conspiracy.

Theistic apologies debunked

Hat tip to Prof. PZ Myers of Pharyngula. PZ wrote:

This is a wonderful video debunking the Kalam Cosmological Argument. What I really like about it is that it takes the tortured rationales of theologians like William Lane Craig, who love to babble mangled pseudoscience in their arguments, and shows with direct quotes from the physicists referenced that the Christian and Muslim apologists are full of shit.

So the theists cherry-pick misunderstood factoids from science to steal the legitimacy of scientific research for their myths. Then if someone points out that the research has changed its answer, they whine about the lack of evidence? I think my irony meter just sproinged its guts all over the room.

But are their cherries Jesus-approved? (Hat tip to Greta Christina:

“They cherry-pick scripture to support their position; you cherry-pick scripture to support yours—how do you know that your cherries are the ones Jesus would approve of?”

and Hamstur:

Now there’s a starburst for every Christian author’s book: “My cherries are Jesus approved!”


From Saturday Morning Breakfast Cereal:

Hubble Deep Field images

First came the Hubble Deep Field, a long look into a tiny speck of black sky that revealed almost 3000 previously unknown galaxies:

Hubble Deep Field image

The image was constructed from a series of observations by the Hubble Space Telescope. It was assembled from 342 separate exposures taken with the Space Telescope’s Wide Field and Planetary Camera 2 over ten consecutive days between December 18 and December 28, 1995.

Then there was the Hubble Deep Field South, taken in the southern hemisphere:

Hubble Deep Field South image

The observations were made over 10 days in September and October 1998. The southern image reavealed about 3000 galaxies and it included a quasar.

And finally the Hubble Ultra Deep Field:

Hubble Ultra Deep Field image

The images were collected from September 24, 2003, through to January 16, 2004. The ultra-deep image looks back about 13 billion years. In August and September 2009, infrared data was collected from a new camera.  With the infrared data, astronomers identified some very distant, and very early, galaxies. The image contains about 10,000 galaxies, many of them deeply red-shifted.

This video (hat tip harleyk) helps to explain it all:

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