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21 Jun 2011
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Science has advanced to the point where we can infer something about the entire universe. This has been a great challenge considering how unimaginably vast the universe is. The countless stars you see in the darkest sky constitute merely 3000 neighbors out of about 300,000,000,000 stars in our galaxy, and as many as 100,000,000,000 galaxies exist in the universe. Humans have always wondered: Has the universe always existed like we see it now, or did it somehow start all of a sudden? In the beginning of this past century, we found out in amazement that the entire universe is expanding. This led physicists to deduce that the universe started out in the finite past with a minuscule size. Realizing that the universe had a beginning, and awed by its vastness and its creations, people have asked: How did the universe begin? After all, we are here to be amazed by it because the universe eventually created lives like us. Now, after decades of observing and thinking, we have come to answer confidently the question of the origin of our universe... with what is known as the "big bang".

18 Jun 2011
Published in Blog

Light is simply a name for a range of electromagnetic radiation that can be detected by the human eye. What is electromagnetic radiation, then?

 

Electromagnetic radiation has a dual nature as both particles and waves. One way to look at it is as changing electric and magnetic fields which propagate through space, forming an electromagnetic wave. [illustration] This wave has amplitude, which is the brightness of the light, wavelength, which is the color of the light, and an angle at which it is vibrating, called polarization. This was the classical interpretation, crystallized in Maxwell's Equations, which held sway until Planck, Einstein and others came along with quantum theory. In terms of the modern quantum theory, electromagnetic radiation consists of particles called photons, which are packets ("quanta") of energy which move at the speed of light. In this particle view of light, the brightness of the light is the number of photons, the color of the light is the energy contained in each photon, and four numbers (X, Y, Z and T) are the polarization.

01 Jun 2011
Published in Blog

What is a black hole? When do black holes form? Can scientists see a black hole? What is the "event horizon" of a black hole?

A black hole is a theoretical entity predicted by the equations of general relativity. A black hole is formed when a star of sufficient mass undergoes gravitational collapse, with most or all of its mass compressed into a sufficiently small area of space, causing infinite spacetime curvature at that point (a "singularity"). Such a massive spacetime curvature allows nothing, not even light, to escape from the "event horizon," or border.

Black holes have never been directly observed, though predictions of their effects have matched observations. There exist a handful of alternate theories, such as Magnetospheric Eternally Collapsing Objects (MECOs), to explain these observations, most of which avoid the spacetime singularity at the center of the black hole, but the vast majority of physicists believe that the black hole explanation is the most likely physical representation of what is taking place.