Episode 12 Encyclopaedia Galactica

Some topics seem like they haven't changed much over the last 33 years. Whether we have been visited by extraterrestials is one of those topics. I agree with Carl that extraordinary claims require extraordinary evidence. So far, there doesn't seem to be any credible evidence that contact has been made.

The Drake equation that estimates the number of civilizations within the Milky Way galaxy has also stood the test of time.The fact that we have found over 1000 exoplanets has increased the validity of the estimates for the leftmost factors in the equation. I've seen estimates that there are 33 billion Earth-sized planets in the habitable zones of their stars. Carl calculated that there were 100 billion planets with life.

The moon systems of Jupiter and Saturn have also proved that planets are not necessarily the only places to look for life. The chance that Mars had or has simple life has increased with the rovers discovering rocks that could have formed only in liquid water. The moons Europa, Enceladus and Titan all have their proponents for current life because they have liquid lakes and oceans.

The more uncertain factors are on the right side of the equation. The most uncertain one is "how long do civilizations last?" and that is a political question rather than scientific one. Carl calculated that there has been 1 billion planets with civilizations with radio communication. But when you use the fact that mankind has had radio communication capability for only a few decades of the Earth's 4.5 billion years, you have to multiply those 1 billion civilizations by (45 years / 4.5 billion years) 1/100,000,000 with a result of 10 civilizations currently in existence.

The observation that there should be aliens all over the place but we haven't seen them yet, is called the Fermi paradox. Carl proposes a couple of reasons for their absence. Possibly were the first ones on the block and the others are still in development. Another possibility are that they are here already. Observing us discretely without letting their presence be known. A third possibility is that civilizations become complacent and lose their drive to explore. Sometimes with the reduced support for science in the US, I'm worried that could be the direction we are headed in. A future with people so preoccupied texting what they had for breakfast with their smart phones they don't have any interest in looking at the stars in the sky anymore.

One of the recent topics up for debate is whether we should attempt to communicate by sending signals from Earth. Stephen Hawking thinks it is a bad idea. The odds are that any civilization we contact would be far more advanced than we are. Historically things haven't gone well when a backward civilization meets a much more advanced one, Aztecs vs the Spanish for example. I still remember the Twilight episode entitled "To Serve Man". The Earth thought it was a book on how the aliens would teach Mankind about all their great scientific discoveries but it turned out to be a cookbook. Maybe we can intercept that signal we sent to the globular cluster M13.

Episode 11 The Persistence of Memory

Life is complex and Carl assumes with the vastness of the cosmos, other instances of intelligent life must exist. And yet we have the Fermi paradox that we have not seen or heard any other civilizations. My feeling is that the civilizations are so far apart in the cosmos, we are effectively all in separate cages in a cosmic zoo. Everyone is effectively trapped through space and time from contacting one another.

It is an interesting concept to connect the information in genes with the information content of the brain and finally the information stored within our books. Each step exponentially increases the amount of storage capability.

I've heard one theory that man is not the top of the pyramid of life. We are merely the means that DNA uses to keep its message replicating through time. DNA has been at it for several billion years. We may come and go as a life form. DNA will find another host to keep its immortal chain letter continuously being replicated through time.

Episode 10 The Edge of Forever

There are some great galaxy pictures in this episode especially considering that the corrected Hubble Telescope was more than a decade away.

I thought the flatland segment was way overdone and I never heard of the tesseract which is a 4-dimensional cube. I guess a lot of this discussion was the precursor to string theory and its additional dimensions.

The current theory on the universe is that it has just the necessary amount of mass to be flat with only a .4% margin of error. If the universe had more matter it would have curvature of a sphere and less matter would create a saddle shape.

Carl has really done his analysis of various cultures. I find it amazing that the Hindu religion has Brahma cycles that last 8.6 billion years.

Another amazing fact is that all the energy intercepted by all radio telescopes from non solar system objects would not equal the energy of a single snowflake hitting the ground.

The last fact is hard to visualize. When you think of the arms of a spiral galaxy rotating, it is not a constant group of stars comprising the arm. The arm is actually defined by a density wave that creates new stars at the leading edges of the arms. The sun as it rotates around the Milky Way actually goes in and out of the spiral arms. The sun is traveling at 486,000 mph so that it can make one galactic revolution in 240 million years.

Carl did a great job of bringing his own perspective to this cosmology episode. I'm really looking forward to Neil De Grasse Tyson's handling of this material in the 2014 version of Cosmos.

Episode 9 The Lives of the Stars

That was a cool statistic at the beginning. If you cut an apple pie in half, 90 times you'll be down to the size of an atom.

Atoms are mainly empty space. In fact the nucleus of the atom is 1/100,000 the size of the full atom with its electron cloud. Now you know why neutron stars that have a mass several times the Sun and have been crushed down to the size of a city, have such a high density. One of Dan Joyce's favorite quotes is that, "if you drop a marshmallow from eye height, it will hit the surface of a neutron star with the energy of an atomic bomb."

I wonder how many people know the origin of the name of the search engine, Google. It isn't spelled the same but the Googol (10 raised to the power of 100) was the source. I never knew that the name came from a mathematician's 9 year old nephew. For future reference, remember a Googolplex is 10 raised to the googol power.

Speaking of big numbers, I recently seen the the number of stars in the universe has been estimated to be 300 sextillion (3 x 10 to the 23rd power). Carl throws out a couple more with, number of atoms in the human body being 10 to the 28th power), number of elementary particles (protons, neutrons & electrons) in the universe being 10 to the 80th power, and the entire universe packed with neutrons would be 10 to the 128th power.

I thought the observation of the neutrino flux from the 1987 supernova in the Large Magellanic Cloud galaxy was one of the great scientific accomplishments. It was mentioned that astronomers were only finding 1/3 the theoretical flux of neutrinos from the Sun. Subsequently, scientists found that neutrinos can change between 3 flavors, electron, muon and tau. The detectors scientists were using could only detect 1 of the 3 flavors. That's why they were only seeing 1/3 of the neutrinos. I didn't realize that it took until 2001 for scientists to confirm this.

Episode 8 Travels in Space and Time

The Cosmos series was pulled from Hulu just when I was really hooked on it. Even Hulu+ didn't help. Fortunately my library came through with the series on DVD. So it looks like I'll be able to finish but I've got to get through 4 more episodes in 2 weeks.

Carl brings out the concept of chaos where small changes can make a big difference in the outcome of systems especially if enough time has elapsed.

He makes a point to show that the star patterns in the sky change through time and space. They also change due to the aging of stars.It is also fun to realize that when you look up at the sky, you're looking back in time. All the stars in the sky are members of the Milky Way galaxy so rarely are we looking at anything farther than a few thousand light years away. The Andromeda galaxy is the farthest object that can typically be seen with the naked eye and it is 2.5 million light years away. With my 8" telescope, I've seen the 13th magnitude quasar 3C273. It is really neat to contemplate that the photos hitting your eye from that object have been traveling for 2 billion years.

The designs of the star traveling spaceships haven't changed much over the years. I remember when the Orion design came out with propulsion provided by exploding nuclear bombs behind it. I never was too confident that way a good way to travel.

It was quite a coincidence that Carl was sitting in the time machine from the 1960 movie with Rod Taylor. I had just recorded the movie on my DVR and am trying to convince the grand kids that they want to watch so they can see the Eloi fight the Morlocs.

Episode 7 The Backbone of Night

When Carl romances about what the ancients knew, it is humbling to recognize that people 2500 years ago were pretty smart. The Ionians believed things were made from atoms, humans sprang from simpler forms of life, diseases were not caused by demons, Earth was a planet going around the sun and stars were far away. I wasn't sure where Ionia was but a map in the "Cosmos" book showed that it was the western side of modern day Turkey and just across the Aegean Sea from Greece. He attributes their forward thinking to the lack of a strong civil government and no controlling religion.

Eventually more mystical thought and oppressive governments overtook the Ionian way of thinking. It took the Enlightenment of the 1600's to rediscover many of these early truths. Imagine how much more science might have advanced if we didn't take the 2000 year detour.

There was no 1995 update by Carl on this episode. Probably because he had the exoplanet search and size of the universe pretty up-to-date. He mentions that the Milky Way contains a few hundred billion stars and that there are about 100 billion galaxies. These numbers are what scientists today think are accurate. I've seen within the last year that they estimate that there are 300 sextillion stars in the universe (3 followed by 23 zeros). There are more stars than grains of sand on all the beaches of Earth!

The exoplanet count is now up to 755. The vast majority where discovered by spectroscopic studies where they follow how the stars move toward us and then away from us as the planets revolve around them (blue-shifting and red-shifting of spectral lines). The Kepler satellite used the method of  rhythmic star dimming due to planets passing in front of the star, to find planet candidates.The number of Kepler unconfirmed candidate planets is 3470. I've seen a recent estimate of 33 billion habitable-zone earth-like planets in the Milky Way. I'm sure that statistic would have brought a smile to Carl's face.

Let us support space and science endeavours so that we can fulfill his final comment that, "Man is ready to set sail for the stars." I think he'd frown a bit to see how little we have advanced since 1980 in some areas.