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SPEAKER: Let us now come closer to our home, the solar system. In other words, our sun is the dominant object in the solar system. And these are the planets. And I include Pluto-- I don't see why not-- in this realm of the planets.
And the sun is a huge fireball. It's so big you can put one million Earths inside the sun, just to give you an idea that really the dominant object in the solar system is really our star, the sun. The planets don't even make one fraction of 1% of the mass in the solar system.
And the sun, being a fireball, it always explodes. It has fires on it, storms that fly out and collect backwards and fall back into the sun. It's completely gorgeous. And it survives in equilibrium, more or less, for billions of years until, as I mentioned, will exhaust its nuclear fuel.
Here is a picture of the surface of the sun taken with a satellite that is inspecting the sun continuously to see what kind of storms we will have of solar particles.
This is Venus, one of the closest planets to the Earth. But Venus is always covered with clouds. So we can never really take a good photograph of the surface of Venus. Venus's atmosphere is something like 90 times denser than the Earth's atmosphere. So therefore, there is a big greenhouse effect on Venus, and the temperature happens to be over 800 degrees, so hot that water is evaporated-- not a very pleasant, not a very good place for life.
We made radar pictures of Venus, like the previous ones I showed you. And these synthesized pictures that we have from radar mapping of Venus by penetrating the clouds.
And this is us-- the lovely blue planet that we should treasure and protect for our sake and for the generations to come, with our sister moon that we see. And this is how we look from orbit around the moon-- a distant small, round object.
Believe me, there are still societies out there which are called Flat Earth Societies that are paying dues. They still believe that the Earth is flat. We need much more science education that we have at the present time.
The first step that we have made on another object in the universe-- the moon. In 1969, our brave astronauts, in this case, Neil Armstrong, made the first footstep on another object in the universe. I hope this is not the last one. And I hope that humans will actually go out and explore the solar system and beyond in a long time to come from now.
Our moon looks beautiful and gives us a lot of light at night when it's very dark. Once a philosopher was asked, what was more important, the moon or the sun? And the philosopher said, that's a tricky question. It is the moon. Because at night when everything is dark, the moon at least gives us some light, he said. But in the daytime when it's light everywhere, who needs the sun? We need more science education, by the way.
The other most interesting planet is Mars. We now are exploring Mars very closely. Here, you see almost a very huge Grand Canyon on Mars. A few decades ago, we landed a spacecraft on Mars. We took photographs, and it looked like a desert. There were no trees, no forests, no beaches, no giraffes, no lions, no little green men. It was just like a desert. It looked reddish because there is iron oxide on the surface.
And then about 10 years ago, we sent a little robot, our Pathfinder, that went around literally just a couple of feet across. It went around, said hello to the rocks, tried to find their composition, did some experiments. And Mars seemed to be very interesting place to study.
So NASA asked us to actually study much closer. We were already photographing Mars with satellites around Mars. And we were able to see these kind of formations that indicated perhaps that water was there some time ago and carved those features.
And NASA asked us to build two big rovers-- Spirit and Opportunity, we called them-- here at Cornell, with Professor Steve Squyres being the principal investigator. And they landed successfully. And they're in the last three years, they've been roaming Mars, studying every aspect of it.
What has become clear is that long time ago, it is very possible that Mars actually had flowing water. We are not sure about any life on Mars. There doesn't seem to be any right now, at least from the experiments we have made. But it doesn't look like another beautiful paradise where we can have immigrations to start with tomorrow.
Immediately, we started drilling the stones, as you can see in this photograph, to study their composition and learn about the geology, if you wish, of Mars. But Mars looks barren. It is like a desert. And we will continue to explore it.
Between Mars and Jupiter, there are tens of thousands literally of smaller objects we call asteroids. Probably, when the solar system was formed, there was one or two planets between Mars and Jupiter that probably collided and cracked up into tens of thousands of pieces and formed these asteroids. They look like potatoes. They see-- you can see they are cratered, with many, many impacts or so.
They are about 10 kilometers, 30 kilometers, some of them are hundreds of kilometers across. You don't want one of these to come and collide with the Earth. That would be very catastrophic.
This is Jupiter, the largest planet in the solar system. It has a very intricate atmosphere full of hurricanes. And you can see here what we call the red spot, that actually Galileo Galilei saw it some 300 years ago when he turned the telescope to see Jupiter. And it still persists-- a very interesting atmosphere that we have learned a lot about atmospheric circulations, and we have applied that knowledge to our own atmosphere on Earth.
But Jupiter has most interesting moons, satellites. This is the satellite Io. And everywhere you see it's dark spot, it's because it's hot. It's the mouths of volcanoes. It is just completely covered with volcanoes and changes the topography very often because of the volcanic ashes.
And this is Europa. The surface of Europa, those are not highways that you see there. It is actually cracked ice. The surface is covered with ice. It's very cold. There could be an ocean below the ice-- a most interesting place for us to explore.
The next planet is this majestic object, Saturn, with its rings around it. The rings are actually made of little particles about one or two inches in size-- millions and millions of them moving around in the equatorial plane of Saturn. The particles are too close to Saturn, and they were not able to coalesce to form satellites because of the strong gravity of Saturn.
Recently, we have sent a probe there called Cassini, which is now probing the Saturnian system of its satellites and rings. This is a close-up view taken by the Cassini spacecraft of the ring system of Saturn, that you actually see hundreds and hundreds of ringlets next to one another.
Other objects in the solar system that we see very well and know are called comets. Comets are actually very little or very small objects, maybe 2 or 3 or 5-- maybe 5 or 10 kilometers in size. They are something like dirty snowballs that probably are the remnants of the primordial cloud that formed the sun and the planets.
And as they move around, the gravity of the sun, and sometimes the gravity of Jupiter, attracts these little objects closer and closer in to the sun. And the sun's heat heats them up, melts the surface, and evaporates the gases. And as they go around the sun, they leave these beautiful tails. Here is Hale-Bopp, a recent comet that everyone was able to see with the naked eye.
Now, we do all these things from the ancient times to the present with the assistance of observatories, of instruments, technology, from all the way from the Stonehenge thousands of years ago to today, the Palomar telescope in Southern California, which is a big optical telescope, 5 meters in diameter, that Cornell operates, together with the California Institute of Technology.
But we also get energy from the sky and from galaxies at radio waves, not just at optical waves. For that, we have to build radio telescopes. And Cornell built the world's largest radio telescope on the island of Puerto Rico in the early 1960s called the Arecibo radio telescope.
You see a photograph of this huge dish-- a radar dish-- with a diameter of thousand feet. And the superstructure hanging at the top to collect the energy from the dish, as the energy comes from the sky down to the dish, reflects out from there to these focal points. And we studied the universe of galaxies very far away.
This enormous knowledge that we have now amassed about the universe. As T.S. Eliot said, "We shall not cease from exploration. And the end of all our exploring will be to arrive where we started and know the place for the first time."
Join Yervant Terzian in a discussion of "why is there a universe? Why is there something rather than nothing?" and examine how humans think about their place in it.
This video is part 2 of 3 in the Cosmology and the Anthropic Principle series.
