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zuz
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We know interstellar space and intergalatic space is not empty. Couldn't small dust particles block the light of distant galaxys?
To answer that, you have to consider just how close to empty intergalactic space is. It is estimated that that it contains roughly one particle per cubic meter, So if you had a one meter square column of intergalactic space 10 billion light years long, it would contain about 9.5 x 1025 particles, and this would be what would be between you and a galaxy 10 billion light years away.zuz said:We know interstellar space and intergalatic space is not empty. Couldn't small dust particles block the light of distant galaxys?
Only if it were much, much, much closer to us than that galaxy. Grains of dust don't stand still and are in constant motion. The closer the particle is to us, the greater its apparent motion. For example, a dust mote 1 meter away moving sideways at cm/s has an apparent angular motion of 0.57 degrees per sec. It would cross more than the width of the full Moon in a sec. At 2 meters away its angular motion drops to 0.285 degrees/sec and it would take twice as long to cross the width of the Moon. However, its angular size would also decrease in half and it would block a much smaller part of the Moon as it passed.zuz said:What I'm saying is that one grain of dust, between us and a distant light sourse is enough to block that light sourse.
There are probably particles much larger than that floating out there. I don't see why planet sized chunks of material can't be out there. They have been found in the galaxy. Couldn't one cover a whole slew of galaxys?
zuz said:. I don't see why planet sized chunks of material can't be out there.
The whole atmosphere weighs as much as 10 m of water, or 76 cm of quicksilver, or about 5 m of soil. Look under your feet. You cannot see through 76 cm quicksilver or 5 m soil, and only see anything through 10 m water if it is unusually clear lake or sea.Janus said:To answer that, you have to consider just how close to empty intergalactic space is. It is estimated that that it contains roughly one particle per cubic meter, So if you had a one meter square column of intergalactic space 10 billion light years long, it would contain about 9.5 x 1025 particles, and this would be what would be between you and a galaxy 10 billion light years away.
This seems like a a lot. However, one cubic meter of air at sea level contains 5.2 x 1025 particles, and so a one meter square, two meter long column of air has more particles in it than that 10 billion light year long column of intergalactic space. Two meters of air doesn't block much light.
If the Earth's atmosphere were of constant density, it would be 8.5 km thick, which is how much air we are looking through when we look out at the night sky. This means that our atmosphere blocks many, many, many times more light that is lost over the 10 billion year distance of intergalactic space.
zuz, I don't understand the point of your question. As Janus has pointed out, it could only happen (if at all) under the most particular circumstance but even if it DID happen, my question to you is, so what? Why does it matter? What is it you are really trying to find out?zuz said:We know interstellar space and intergalatic space is not empty. Couldn't small dust particles block the light of distant galaxys?
Yes. Starting with Great Rift of Milky Way.zuz said:What I would like to know is are there any voids in our line of sight that could be caused by dust, particles, planets...etc.
zuz said:Density of air is no comparison. It's too close. I can block out the moon with my thumb. If you look at Mars on any given night, it is probably blocking the light of at least a few galaxies, if the Hubble Ultra Deep Field is a example of the entire sky. Yes, planets move. I'm not arguing that. What I would like to know is are there any voids in our line of sight that could be caused by dust, particles, planets...etc.
zuz said:thumb. If you look at Mars on any given night, it is probably blocking the light of at least a few galaxies, if the Hubble Ultra Deep Field is a example of the entire sky. Yes, planets move. I'm not arguing that. What I would like to know is are there any voids in our line of sight that could be caused by dust, particles, planets...etc.
OK, well, I'd say you are WAY WAY off base on that thought, as Janus has already explained.zuz said:My point is maybe we're not seeing the whole picture.
And, as Janus alludes to, when your shutter speed minutes, hours or even days, even that problem goes away.stefan r said:So at most you lose one star system in a galaxy with billions of stars.
Interstellar dust is a collection of tiny particles, including silicates, carbonaceous material, and ices, that exist in the space between stars in a galaxy. These particles are created from the remnants of stars and are constantly replenished through processes such as supernovae explosions.
Interstellar dust particles are small and widely dispersed throughout space, but they can still have a significant impact on the light that travels through the universe. When light from a distant galaxy passes through an area with a high concentration of interstellar dust, the dust particles absorb and scatter the light, making it difficult for us to see the galaxy clearly.
No, interstellar dust cannot be seen with the naked eye. These particles are incredibly small, with sizes ranging from a few nanometers to a few micrometers, and are not visible to the human eye. We can only observe interstellar dust through specialized instruments, such as telescopes and spectrometers, that can detect the effects of the dust on light.
The amount of interstellar dust in a galaxy can vary significantly depending on its location and age. Younger galaxies tend to have higher concentrations of dust due to the recent formation of stars, while older galaxies may have less dust as it has either been consumed by star formation or has been pushed out of the galaxy by stellar winds and explosions.
Studying interstellar dust is crucial for understanding the formation and evolution of galaxies and the universe as a whole. The dust particles play a role in the formation of new stars and planets, and they also influence the chemical composition of gas clouds in the universe. By studying interstellar dust, we can gain insights into the processes that shape our universe and how it has evolved over billions of years.