In a world dominated by magical thinking, superstition and religion, give yourself the benefit of doubt. This is one skeptic's view of the Universe.
"Tell people there’s an invisible man in the sky who created the universe, and the vast majority believe you. Tell them the paint is wet, and they have to touch it to be sure."
“If people are good only because they fear punishment, and hope for reward, then we are a sorry lot indeed”.
“Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense.”
The person who is certain, and who claims divine warrant for his certainty, belongs now to the infancy of our species. It may be a long farewell, but it has begun and, like all farewells, should not be protracted.
Astrophysics is a branch of space science that applies the laws of physics and chemistry to explain the birth, life and death of stars, planets, galaxies, nebulae and other objects in the universe. It has two sibling sciences, astronomy and cosmology, and the lines between them blur.
In the most rigid sense:
-Astronomy measures positions, luminosities, motions and other characteristics
-Astrophysics creates physical theories of small to medium-size structures in the universe
-Cosmology does this for the largest structures, and the universe as a whole.
In practice, the three professions form a tight-knit family. Ask for the position of a nebula or what kind of light it emits, and the astronomer might answer first. Ask what the nebula is made of and how it formed and the astrophysicist will pipe up. Ask how the data fit with the formation of the universe, and the cosmologist would probably jump in. But watch out — for any of these questions, two or three may start talking at once!
Goals of astrophysics
Astrophysicists seek to understand the universe and our place in it. At NASA, the goals of astrophysics are “to discover how the universe work, explore how it began and evolved, and search for life on planets around other stars,” according NASA’s website.
NASA states that those goals produce three broad questions:
How does the universe work?
How did we get here?
Are we alone?
It began with Newton
While astronomy is one of the oldest sciences, theoretical astrophysics began with Isaac Newton.
Prior to Newton, astronomers described the motions of heavenly bodies using complex mathematical models without a physical basis. Newton showed that a single theory simultaneously explains the orbits of moons and planets in space and the trajectory of a cannonball on Earth. This added to the body of evidence for the (then) startling conclusion that the heavens and Earth are subject to the same physical laws. [Related: How Isaac Newton Changed the World]
Perhaps what most completely separated Newton’s model from previous ones is that it is predictive as well as descriptive. Based on aberrations in the Newtonian orbit of Uranus, astronomers predicted the position of a new planet, which was then observed and named Neptune. Being predictive as well as descriptive is the sign of a mature science, and astrophysics is in this category.
Milestones in astrophysics