Ice Formation in a Protoplanetary Disk - Credit: NASA/JPL-Caltech/R. Hurt
Water is crucial for life, but how do you make water? Cooking up some H2O takes more than mixing hydrogen and oxygen. It requires the special conditions found deep within frigid molecular clouds, where dust shields against destructive ultraviolet light and aids chemical reactions. NASA’s James Webb Space Telescope will peer into these cosmic reservoirs to gain new insights into the origin and evolution of water and other key building blocks for habitable planets.
A molecular cloud is an interstellar cloud of dust, gas, and a variety of molecules ranging from molecular hydrogen (H2) to complex, carbon-containing organics. Molecular clouds hold most of the water in the universe, and serve as nurseries for newborn stars and their planets.
Within these clouds, on the surfaces of tiny dust grains, hydrogen atoms link with oxygen to form water. Carbon joins with hydrogen to make methane. Nitrogen bonds with hydrogen to create ammonia. All of these molecules stick to the surface of dust specks, accumulating icy layers over millions of years. The result is a vast collection of “snowflakes” that are swept up by infant planets, delivering materials needed for life as we know it. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
'Would you like to see the menu?' he said,
'or would you like meet the Dish of the Day?'
'That's cool,'' said Zaphod, 'we'll meet the meat.''
A large dairy animal approached Zaphod Beeblebrox's table, a large fat meaty quadruped of the bovine type with large watery eyes, small horns and what might almost have been an ingratiating smile on its lips.
''Good evening', it lowed and sat back heavily on its haunches,
''I am the main Dish of the Day. May I interest you in the parts of my body?'
'That's absolutely horrible,' exclaimed Arthur, 'the most revolting thing I've ever heard.'
'What's the problem Earthman?' said Zaphod, now transfering his attention to the animal's enormous rump.
'I just don't want to eat an animal that's standing there inviting me to,' said Arthur, 'It's heartless.'
'Better than eating an animal that doesn't want to be eaten,' said Zaphod.
'That's not the point,' Arthur protested. Then he thought about it for a moment. 'Alright,' he said, 'maybe it is the point. I don't care, I'm not going to think about it now. I'll just ... er ... I think I'll just have a green salad,' he muttered.