by Chris Peterson » Thu Jan 19, 2017 3:27 pm
moconnor wrote:When I think about dust, I think about the handful of bunnies below my bed or behind my computer. If I collect and compress all of them, they consume less than a thimble and weigh less than a gram. But this Elephant's trunk is 20 light years long! It's hard for me to imagine that much dust. Does that much dust weigh more than the Earth? Jupiter? the Sun?
A nebula like this has many, many solar masses. That's how come they are able to produce stars. Keep in mind, however, that this is basically a gas nebula, most of which is invisible. The dust only represents one or two percent of the total, the majority of which is hydrogen. And even though the total mass is hundreds of solar masses or more, that's distributed over many cubic light years, so the density of the entire thing is still lower than what we'd call a hard vacuum. It's massive only because it's huge, not because it's dense.
Also, if I were to collect a sample of that dust and analyse it, what would it be made of? Sodium? Chlorine? Carbon? Gold?
Cosmic dust is the main source of all the heavy elements when it comes to building new stellar systems. So you find in it all elements. But it is substantially made of silicates and carbonates, not all that different from the plain old dust that settles on your windowsill.
[quote="moconnor"]When I think about dust, I think about the handful of bunnies below my bed or behind my computer. If I collect and compress all of them, they consume less than a thimble and weigh less than a gram. But this Elephant's trunk is 20 light years long! It's hard for me to imagine that much dust. Does that much dust weigh more than the Earth? Jupiter? the Sun?[/quote]
A nebula like this has many, many solar masses. That's how come they are able to produce stars. Keep in mind, however, that this is basically a gas nebula, most of which is invisible. The dust only represents one or two percent of the total, the majority of which is hydrogen. And even though the total mass is hundreds of solar masses or more, that's distributed over many cubic light years, so the density of the entire thing is still lower than what we'd call a hard vacuum. It's massive only because it's huge, not because it's dense.
[quote]Also, if I were to collect a sample of that dust and analyse it, what would it be made of? Sodium? Chlorine? Carbon? Gold?[/quote]
Cosmic dust is the main source of all the heavy elements when it comes to building new stellar systems. So you find in it all elements. But it is substantially made of silicates and carbonates, not all that different from the plain old dust that settles on your windowsill.