Galileo's Dream

I'm Back!

2007-06-04T19:46:00.000-07:00

Inspired by a video that lends images to Carl Sagan's speech about the "Pale Blue Dot," I will be posting once again. Sorry to have let the blog lapse.

Bye Bye Pluto (Finally)

2006-08-24T19:07:00.000-07:00

Pluto and Charon, mutually attracted rocks, now called "dwarf planets."

I've been teaching Astronomy for four years, and every year I've told my students that Pluto should not be classified as a planet. Smaller than Earth's moon, it has none of the properties that would make it a true planet in terms of size and composition. Pluto's composition matters in terms of classification because of how the solar system formed (see previous post). There are terrestrial planets nearest the Sun and gaseous planets farther out. Pluto is one of thousands of rocks outside of this gas giant region, and should be grouped accordingly. Its orbit and location should put it in a class with other rocks called "Kuiper Belt Objects" in the outer reaches of the solar system. The only shame is that Pluto's orbit, although highly irregular when compared with the other eight planets, does happen to coincide with Neptune's every once in a while, so it is the closest of the K.B.O.'s. Hopefully this "controversy" will make people want to know more about the formation of the solar system, not less. This change reminds me of why I prefer Science to belief; we can change our minds when new evidence arrives. Thanks to Xena and Quaoar and all of the other big rocks out there!

The CREATION of Earth

2006-07-01T20:10:00.000-07:00

It should be the ACCRETION of Earth, but I was being flippant. If you still fear thunder and lightning, then having a god would make sense. Otherwise, the accretion of particles, pebbles, rocks, boulders, and mountains would make more sense if you considered the force of gravity. An atmosphere would follow, because even gas has gravity (and that's why I chose this particular photograph). And once you have an atmosphere, charges take sides and you get thunder and lightning. More to follow...

How Solar Systems Form, Part I

2006-02-12T16:00:00.000-08:00

Because of the recent discovery of hyperstar solar systems, I thought I should explain the current knowledge we have about solar system formation. In order to understand these structures, a basic knowledge of Newtonian gravitation is in order. Gravity is an attractive force, ruled by two distinct factors: mass and distance. Everything in the universe has mass, with the exception of exotic particles like bosons. Objects with mass are attracted to one another directly in proportion to their mass and indirectly to their distance. What this means is that the more massive something is, the more attractive its force in relation to other things. Conversely, if an object is more distant from another object, it has less of an attractive, gravitational force. On Earth, we do not sense this effect because humans are more attracted to Earth than they are to other people and things. If we were in space, away from gigantic celestial objects, we would be like magnets when it came to smaller things. Paperclips would gravitate toward us. On Earth, paperclips are as drawn to Earth as we are, but in space they would be attracted to the next, more massive thing.

The most abundant element in the universe is hydrogen, and in areas where there is more hydrogen atoms than not, they coalesce to form a protostar ("before or first" star). Like a toilet bowl, everything is drawn around the protostar, some falling into it and some having the mass and tangential velocity to stay in orbit. In the case of our own solar system, there were massive mountains of material called "planetessimals" that would attract to each other to create the inner planets. As the proto-Sun became more massive, and it acquired the gravity in its core to fuse hydrogen into helium, due to the tremendous pressures and temperatures acting on the core. Once fusion began, the Sun (now a "star," instead of a protostar) blew off its outer layer of hydrogen gas to form the outer gas giants, which had their own menial planetessimal cores with enough gravity to hang onto the excess gas.

New Mega Solar Systems Discovered

2006-02-12T10:38:00.000-08:00

Two new solar systems have been detected around hyperstars thirty times more massive than our Sun. Resembling Saturn, these giant stars are surrounded by rings of debris, proving for the first time that planets can actually accrete around stars once thought too large to allow such formations. This discovery, along with the recent sighting of a planet only five times the size of Earth, proves once again that there are not only a nearly infinite numbers of stars in the universe, but also planets!

I wish Giodarno Bruno were alive to see his original ideas realized.

Success!

2006-01-15T12:44:00.000-08:00

We now interrupt this blog to report the successful return of Stardust. Back from a seven-year mission, Stardust is a capsule carrying cometary dust from Wild 2, an ineptly-named comet. Samples were taken from the comet's tail back in 2004, and analyzing the particles will shed new light on the formation of the early solar system. I suppose now is as good a time as any to explain what comets are and where they come from.

Out in the far reaches of the solar system there is a vast region of billions of chunks of ice ranging in size from pebbles to mountains. This region is known as the Oort Cloud, named after the Dutch astronomer, Jan Oort, who first proposed the existence of these icy objects 50,000 A.U.'s away from the Sun. (An A.U. is an astonomical unit; 1 A.U. = 93,000,000 miles or the distance from the Earth to the Sun). Because the rocks are so small and so far away, we cannot see them, but their existence can be inferred from the orbits of the comets that pass through our solar system every once in a while. As the comets get pulled out of the Oort Cloud due to random collisions or the gravitational tug of other stars, they get pulled in toward the gas giants and eventually toward our Sun. As the coma or body of the comet heats up, the ice melts and the comet acquires a tail of glowing (ionized) dust particles. Tails can stretch to distances up to 1,000,000 miles long! A beautiful sight indeed.

Galileo Sees the Light, Again

2006-01-05T19:32:00.000-08:00

The Milky Way was a mystery in Galileo's time. Greek mythology proposed that the band of clouds in the night sky was a remnant of Hera's breast milk strewn in an arc above the northern horizon (hence the "Milky" Way). When Galileo looked at our galaxy with his telescope he could easily see points of light that could only be too far away to have a parallax shift. Why would God create objects that humans couldn't resolve with their own eyes? Once again he was baffled by what he saw, and yet he saw the light.

Coming Soon: The Milky Way Unveiled By Galileo

2005-12-11T16:52:00.000-08:00

Speaking About Saturn...

2005-12-05T17:46:00.000-08:00

There are times when I take a photograph and feel so proud of the composition, light, etc. Click on the image above, baby. Words cannot describe how proud these humans must feel about their collective and stunning achievement of capturing this image (along with countless measurements and invisible observations). Currently there is a satellite exploring Saturn and a probe that has descended onto the surface of the planet's largest moon, Titan. Cassini travelled about 800 million miles and then traversed the rings by going up through a mere 13,000 mile-wide gap, and Huygens landed on Titan to examine its thick atmosphere and icy surface. To get an idea of Saturn's size, imagine Earth as its tiny core and understand that the ring system extends as far as our Moon's orbit!

Titan is of great interest to scientists because it resembles an Earth frozen in time; it retains many properties from its early existence when the solar system first formed because it is so far removed from the heat of the Sun. Titan is larger than Mercury and has an atmosphere ten times as thick as the Earth's. Methane on Titan is in liquid form and has created river-like systems on the surface. Organic molecules including benzene have been detected, and lightning storms have lit up the sky! Truly a Miller experiment in the making. Check out the Cassini-Huygens link on the right to get an in depth analysis of what's currently going on. We should all be proud of NASA, JPL, and the EU for their work on this project.

And just to stun you, here's a picture recently taken by Cassini of a small moon, Mimas, with a backdrop of Saturn's rings:

Galileo Beholds Saturn

2005-11-18T16:02:00.000-08:00

Anyone who has ever seen Saturn with a good telescope knows that it is one of the most beautiful celestial objects. A perfect sphere hovering inside multicolored rings! Spectacular! Yet when Galileo got a glimpse of the planet, he was utterly confused. He understood planets and moons, but rings? He had the language to describe what he saw (and we know what he saw because he made the drawings you see below), and yet he couldn't fathom something so strange. He thought the rings must be moons traveling at great velocities. (And remember, his telescope was anything but primitive).

Galileo's Proof

2005-10-29T13:07:00.000-07:00

Galileo wrote the "Dialogue Concerning the Two Chief World Systems" to illuminate the differences between an Earth-centered or geocentric universe and a Sun-centered or heliocentric one. There were two observations through his telescope that supported the Copernican idea that the Earth indeed orbited the Sun. The first was the fact that Venus showed phases and got smaller and larger in the sky as it orbited the Sun. If Venus orbited Earth, its diameter would not grow and shrink in size (the Moon's didn't!). Venus was largest right before it was in the "new moon" phase of being backlit by the Sun. In this position it would be closest to the Earth. As it made its way around the Sun, it would reflect more sunlight on its surface until the half facing Earth was fully lit (just like a full moon). In this phase it would be much smaller from Earth's perspective.

His second observation was that Jupiter appeared to be a mini-solar system in its own right, with multiple moons orbiting a larger planet. Maybe the planets orbited the massive Sun, just like the moons orbited Jupiter.

If only Galileo could've seen what the four largest moons looked like up close!

They are now known as the Galilean moons, and from the upper left going clockwise are Io, Europa, Callisto, and Ganymede. To date there are 61 moons orbiting Jupiter.

It Spins!

2005-10-21T18:35:00.000-07:00

If only Galileo could see these close up shots of the sunspots!

Galileo's Shocking Discovery

2005-10-21T15:23:00.000-07:00

The imperfect surface of the moon was probably not as shocking to Galileo as the mutable surface of the Sun. Galileo was a proponent of the Copernican, heliocentric "universe," and even Copernicus stated that the Sun represented all that was Good and perhaps represented God himself. What were these curious blisters on the most perfect celestial body in the universe? And why did they move?

Galileo's First Glimpse

2005-10-19T16:34:00.000-07:00

First off, I'll dispel the idea that Galileo invented the telescope; he merely improved upon its design. Unlike any human at the time, however, he chose to point the telescope up to the night sky and document what he saw. He saw that the moon was pockmarked by craters and had a surface that resembled Earth's crust. It was no longer a perfect* celestial body but a whole other world with imperfections. To give you a taste of the resolution of his lenses, here's a shot from a modern telescope (I highly recommend clicking on the image for a better view):

*Although details of the moon's surface could not be seen by the naked eye, the dark splotches of its surface could easily be discerned by any earthling. These splotches were explained by two different ideas: a) the moon was so close to Earth that it was "corrupted" by our sins or b) the moon reflected Earth's continents. (Now we think that the dark regions are three billion year old lava flows instigated by early, Everest-size asteroid impacts.)

What Galileo Would Have Wanted

2005-10-06T18:31:00.000-07:00

I remember relishing the fact that I lived in "interesting times." I was born in 1969, the year we landed on the moon. I had hope about humanity's future, and knew that the key to our survival was an understanding of everything scientific and nothing superstitious or astrology-based. I now teach high school juniors and seniors about astronomy, and I want to spread the word to anyone who may not grasp where they are and what they are made of. Galileo published his ideas in Italian instead of the (scientific) language of Latin so that the public would have a chance to read his ideas. I hope to simplify complex ideas and bring them down to Earth so that anyone can understand the cosmos. Enjoy!