Question

How did astronomers establish that the solar system is not at the center of the Milky Way?

	Because there are very few stars above or below the Milky Way
	Because the number of stars is the same in all directions
	From the fact that the Solar System is on a spiral arm
	By mapping the distances of globular clusters

*can be more than one answer

Answer 1

Space experts have pursued numerous lines of proof to decide the area of the close planetary system in the Milky Way. Be that as it may, a portion of the general procedures can be laid out quickly.

"Discovering one's area in a haze of a hundred billion stars- - when one can't go past one's very own planet- - resembles endeavoring to guide out the state of a woodland while attached to one of the trees. One gets an unpleasant thought of the state of the Milky Way universe by simply glancing around- - a worn out, murky band of light circles the sky. It is around 15 degrees wide, and stars are focused reasonably uniformly along the strip. That perception demonstrates that our Milky Way Galaxy is a leveled plate of stars, with us found some place close to the plane of the circle. Were it not a smoothed plate, it would appear to be unique. For example, in the event that it were a circle of stars, we would see its sparkle everywhere throughout the sky, not simply in a thin band. What's more, on the off chance that we were above or underneath the plate plane by a considerable sum, we would not see it split the sky into equal parts - the shine of the Milky Way would be more brilliant on one side of the sky than on the other.

"The situation of the sun in the Milky Way can be additionally bound by estimating the separation to every one of the stars we can see. In the late eighteenth century, space expert William Herschel attempted to do this, reasoning the earth was in the focal point of a 'grindstone'- molded haze of stars. Be that as it may, Herschel didn't know about the nearness of little particles of interstellar residue, which darken the light from the most removed stars in the Milky Way. We seemed, by all accounts, to be in the focal point of the cloud since we could see no further every which way. To an individual attached to a tree in a foggy woods, it would appear that the timberland extends similarly away every which way, wherever one is.

"A noteworthy leap forward in moving the earth from the focal point of the world to a point around 3/5 far from the edge came in the early many years of this century, when Harlow Shapley estimated the separation to the enormous groups of stars called globular bunches. He discovered they were conveyed in a round circulation around 100,000 light-years in distance across, fixated on an area in the group of stars Sagittarius. Shapley closed (and different space experts have since confirmed) that the focal point of the circulation of globular groups is the focal point of the Milky Way too, so our system resembles a level circle of stars inserted in a circular cloud, or 'corona,' of globular bunches.

"In the previous 75 years, space experts have refined this image, utilizing an assortment of procedures of radio, optical, infrared and even x-beam stargazing, to fill in the subtleties: the area of winding arms, billows of gas and residue, centralizations of moleculesand so on. The fundamental present day picture is that our close planetary system is situated on the inward edge of a winding arm, around 25,000 light-years from the focal point of the cosmic system, which is toward the star grouping of Sagittarius.