Can we harvest H & O from space to make water?
I read that mountain ranges were most likely formed by continents crashing into each other. I am wondering if elements on the peiodical table formed in a similar way, i.e. by crashing together at tremendous speeds long ago. Of the elements we know, do we know, or hypothesize, about how their original bonds were set?
Can humans make water by combining H and O? If not, why not? If yes, why are we so worried about water shortages? Couldn't, in theory, water be harvested from space? Are people working on that prospect?
I am just a mom, trying to answer some of my son's questions. He is in middle school. We live in Korea, so it is tough to find appropriate materials in English for his level.
There are a few reasons why we cannot make water by harvesting hydrogen and oxygen from space. First, you CAN make water by combining H and O, but the reaction is really slow at "normal" temperatures. You need some sort of catalyst (like lighting the H and O with a match) to get things going. Thus you could only get the water at the price of some energy. A second problem is that when the reaction does get sparked, it creates a HUGE blast. (Have you heard of the Hindenburg zeppelin that exploded in 1937 in New Jersey? These explosions can be very dangerous!) Assuming that we found a way to get around all of these issues, we would still have trouble bringing the hydrogen and oxygen to Earth from space. The amounts we would require would be very heavy and thus the fuel required for such missions would be quite costly. Not to mention the safety issues of transporting a flammable gas!
As for the other part of your question, not all the elements on the periodic table were formed the same way. Hydrogen, helium, and trace amounts of lithium (the three lightest elements) were formed during the Big Bang at the creation of the universe.
So where do all the other elements come from? There is a popular quote by astronomer Carl Sagan: "We are all made of star stuff." Any of the elements heavier than lithium were produced through nuclear reactions in the cores of stars. For instance, after our Sun is finished burning through all of the hydrogen in its core (something that won't happen for another 5 billion years or so), it will begin to burn helium to form carbon by way of something called the triple alpha process. The sun is a relatively low-mass star, so the burning process ends there, but in more massive stars, oxygen can then be formed by fusing carbon and helium. The more massive a star, the heavier elements it can create. Stars cannot form elements heavier than iron, however, because such reactions require energy rather than create it. The whole reason for undergoing nuclear fusion is to create energy to help the star support itself against gravitational collapse.
The heaviest elements (i.e. heavier than iron) are formed when particles are thrown together at high speeds during a supernova explosion. (See our page on supernovae for more details on these spectacular events.)
Get More 'Curious?' with Our New PODCAST:
- Podcast? Subscribe? Tell me about the Ask an Astronomer Podcast
- Subscribe to our Podcast | Listen to our current Episode
- Cool! But I can't now. Send me a quick reminder now for later.
How to ask a question:
If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist
This page has been accessed 13974 times since April 26, 2006.
Last modified: April 26, 2006 6:51:43 PM
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.
Warning: Your browser is misbehaving! This page might look ugly. (Details)