Bigger than the planet Mercury, Titan is hidden by a thick orange haze. No one has ever seen its surface. But a small probe named Huygens, released by Cassini, is about to change everything. This mission will challenge long held notions of where life could exist beyond Earth.
These are the actual images Huygens takes, as it breaks through the clouds and haze. Titan is a land of mountains and valleys, a place that looks surprisingly like Earth. Then, images reveal something no one expects: the surface is littered with smooth rocks, the type normally found in riverbeds on Earth. We look out on the surface, and we see what looks like a desert, and, at the same time, the data from the probe told us that the ground around the site was wet. The images show a landscape covered with what appear to be hundreds of lakes. This one covers an area of 6, square miles, about the size of Lake Ontario, one of the Great Lakes.
The WIRED Guide to Aliens
It's a surprising discovery. Titan is minus degrees Fahrenheit. If it's water, it should be frozen solid.
Then, one of Cassini's instruments analyzes the infrared light reflected off the lakes. The readings are consistent, not with water, but with liquid methane and ethane, substances that, on Earth, are volatile, flammable gases. The data from Cassini are so detailed, scientists can imagine what it would be like to stand on this cold, distant world.
Here we see lakes, lakes of liquid methane. And in the horizon we see mountains. These are mountains made of ice, made of water ice, frozen so hard that it acts like rocks.
And the features that we see in them are carved by the liquid methane that's forming these lakes. Looking across the horizon on Titan, you might see a thunderstorm or a range of thunderstorms coming at you. We see rain coming down. It's not drops like we're familiar with on Earth; this is methane, instead of water. It falls much more slowly, due to the low gravity, and the drops are bigger. But if such evidence were found here, it would fundamentally change perceptions about life beyond Earth.
If life could evolve on worlds as drastically different as the earth and Titan, then perhaps life could evolve in many other ways, on many different worlds. Heading out from the sun, the first planet is Mercury. It's an extremely hostile environment. Three times closer to the sun than Earth is, Mercury bakes in degree heat on its side facing the sun, while on the night side, temperatures plummet to minus Mercury is the ultimate desert world.
- Best Man Speech (The 7-STEP GUIDE to Writing a Sensational Wedding Speech & Toast Book 1);
- Stefan Wąż!
- NASA Administrator Jim Bridenstine on Life off Earth - WSJ;
- La Bataille de Bir Hakeim - Une résistance héroïque : Résistance héroïque (Documents, Actualités, Société) (French Edition)?
- NASA scientists and Their Search for Life Beyond Earth (Text Only).
- Tell Tale Terror.
Life of any kind here seems unlikely. Mercury's closest neighbor, Venus, is almost as hostile. Though nearly twice as far from the sun, temperatures here exceed degrees. Decades of observations have revealed a planet shrouded in carbon dioxide and toxic clouds of sulfuric acid. These radar images reveal thousands of ancient volcanoes, on a surface hot enough to melt lead. And with an atmospheric pressure that is 90 times greater than on Earth, it is hard to imagine that anything could live down here. But based on chemical analysis of the atmosphere, scientists believe that water once flowed on Venus' surface.
If life ever did exist here, evidence has yet to be found. The answer lies in three key ingredients. First, all life is made up of organic molecules consisting of carbon, in compounds that include nitrogen, hydrogen and oxygen, among others. Although organic molecules aren't alive themselves, they are the basic building blocks of every living organism. Life also needs a liquid, like water. In water, the basic organic molecules can mix, interact and become more complex. The last ingredient is an energy source, like the sun, to power the chemical reactions that drive all life, from the smallest microbe to us.
When these three ingredients came together, billions of years ago, life found a way to take hold, and, today, persists, even in the most extreme environments, like here: this is the Mojave Desert, Nevada. It is one of the hottest, driest places on our planet. There's an axis of dryness here. Go either east or west it becomes wetter. The rocks provide just enough shade to prevent water from evaporating completely.
We see this layer of green; this is bacteria.
The rock provides a little shelter. It's a little wetter and a little nicer living under the rock than it is in the soil around it. In addition, the white rocks are translucent. Hold them up to the sun and see light coming through. These organisms are photosynthesizing here in the desert, where nothing else will grow, so they're living in a miniature little greenhouse.
For scientists like Chris McKay, the question is, "Is Earth the only planet with the essential conditions for life? One way to know is to investigate how planets like ours formed to have these ingredients in the first place. As a vast cloud of dust and gas collapses in on itself, pressures increase, temperatures at the center rise to millions of degrees, until energy from the early sun blasts away some of the cloud.
This lights up the young solar system, revealing the beginnings of planets. The mystery has always been, "How did this spinning cloud of dust become the massive planets we see today? And how do golf-ball-sized things go from there to ten-meter-sized things?http://shadifactory.com/components/tall/side-effects.php
LIFE ON MARS! by Brig Klyce
How do those go to planetary embryos? And there's a lot of steps in there that we don't quite understand. In , the Japanese probe Hayabusa sets out on an audacious mission. The goal: to land on an asteroid, collect samples of dust and then return them to Earth. The target is asteroid Itokawa, a third of a mile long, and speeding through space at 56, miles per hour. Landing on it would be like trying to hit a speeding bullet with another speeding bullet. It stays just long enough to grab a sample. It will take five years before Hayabusa returns asteroid dust to Earth, but, in the meantime, using lasers on board, Hayabusa takes measurements of Itokawa's size and mass.
These allow scientists to determine the asteroid's internal structure. You probably could just take your hand and just go like this and just push it down into the asteroid. These are the basic parts of building blocks of planets.
- Dragon Ball Z, Vol. 24: Hercule to the Rescue.
- Fahrenheit (Men of Action).
- Potere criminale: Intervista sulla storia della mafia (Saggi tascabili Laterza) (Italian Edition)!
- My OpenLearn Profile.
- Chapter 2. What Is Life?.
- Extraterrestrial Life-Science Tracer Bullet-Library of Congress.
As their gravity increases, they attract even more asteroids, until, eventually, as temperatures rise, they become spheres of rock, with hot molten cores: protoplanets. Computer simulations suggest that within 10 million years of the solar system's birth, up to a hundred protoplanets—ranging in size from our moon to Mars—orbit close to the sun.
So why does the solar system look so different today?
Related The Quest for Mars: NASA scientists and Their Search for Life Beyond Earth (Text Only)
Copyright 2019 - All Right Reserved