What evidence can you cite that the spaces between the stars are not empty?

Answer 1

By studying the distribution and temperature of the hot gasses in a given Galaxie, we can measure how much it is being squeezed by the force of gravity from all the material in the cluster. We can determine how much total material (matter) there is in that part of space.

Remarkably, it turns out there is five times more material in clusters of galaxies than we would expect from the galaxies and hot gas we can see. Most of the stuff in clusters of galaxies is invisible and, since these are the largest structures in the Universe held together by gravity, scientists then conclude that most of the matter in the entire Universe is invisible, or "Dark Matter". There is currently much ongoing research by scientists attempting to discover exactly what this dark matter is, how much there is, and what effect it may have on the future of the Universe as a whole.

Hope that helps, have fun!

Answer 2

Well, as far as we know nearly all the space between the stars is, for all intents and purposes, empty.

It is believed that there is a huge amount of 'dark matter' out there based on what we understand about physics. However what and where this matter is (or is not) is still a matter of heated debate.

Space is absolutely vast and much of it contains nothing at all.

Answer 3

Cosmic Microwave Background Radiation (CMBR) & Background X-ray radiation.

M theory also suggests that every point in space-time is occupied by curled up dimensions if you subscribe to that.

Answer 4

Despite the contrary, empty space isn't really that empty. It's filled with different kinds of stray energies, matter, or other spatial debris leftovers.

Answer 5

Absorption lines in stellar spectra.

Answer 6

I cannot cite any evidence to you. But, radio astronomers or space probes could do so.

We are in the unusual position of having to look at another solar system from outside, i.e., looking into their sun. So, we generally are always looking at the back side (dark) of all possible planets and moons within that solar system. And, while we might occasionaly see something, for the most part our eye (or optical seeing equipment) is blinded by the light of that (sun) star. Therefore we cannot see other objects well.

Radar beams, however, could bounce off of the non-solar objects and be collected in a receiving set up quite nicely.
In fact that is being done as we speak by many space probes out there right now.

So to recap, if you placed a probe in a given vicinity and it had on board radar equipment, it could send out radar pulses for a long distance and listen for return echos from anything that the radar pulses hit and reflected back from. There is a limit on distance range of various radar systems, however. Searches way out into deep space require massive antennas and extremely long echo return (listening) pauses between each radar pulse. Most current space probes are limited in the size of their antenna arrays and the maximum pulse power from their on board radar sets. So their ability to reach WAY out is limited.

Here on Earth they have built several massive antenna arrays inside of volcano craters especially for this purpose. Those arrays are capable of fantastic reception ranges. To increase their capability, software has been developed to combine the listening power of multiple observatories together and produce even more powerful listening stations that could hear the echoed pulse returning from far, far distant objects. So those observatory sites could produce the information you seek. Consider looking at site: "Curious about Astronomy"
which you can find by doing a Google serach. Another one is "Space dot com".

Lastly, let me suggest to you that the spaces between stars are most certainly not empty of "everything." Each star you see with what ever devices you choose to use is capable of having from 0 to 10 (or more) planets with all of their associated moons just like our star (the Sun) does. Some planets have rings of dust and unaccumulated debris circling around them. Some particle rings around various planets extend out for thousands, even millions, of miles from the surface of those planets. I would not call that space exactly "empty." The term is possibly vague in that some degree of fullness needs to be suggested to really be effectively used in conversation.

For example: Does the presence of one speck of dust within a million cubic miles of space denote emptyness, or partial fullness? Is a space only completely full when it contains a solid mass of material from one corner to the next of the defined area of discussion? What about gas? If a particular part of space contains gases, but no solid objects, is that part of space empty or full?

Many regions of outer space have massive gas clouds which are absolutely fantastic to look at through telescopes. Those gas clouds, when gathered up into spheres some day will become future stars. They will eventually turn on, and begin shining, when enough gas is accumulated into a ball to generate sufficient heat within the core to kick off a nuclear fusion process. Lest you think that will never happen, let me suggest to you that new stars are being born all the time in outer space. Oh, one other item... What is your conception of the size of outer space? At this time most astronomers agree that outer space can be seen to exist 40 billion light years in every direction from us. That is not the limit of it. That is only as far as we can see with our present optical and radio telescope equipment. So, it is truly vast and beyond most peoples' complete comprehension.

Conclusion of My Answer:

It is wrong to suggest space is empty between the stars. Some further clarification is needed in that statement. There is, however, a large amount of "empty" (contain only occasional specks of dust) space out there in between major objects of significance. Significant objects is meant here to include: Comets and Asteroids larger than a pebble, Moons, Planets, Stars, and Clouds of various scattered gases.