The expansion of the Universe is not constant ... Our Sun is on one of the spiral arms as shown in the diagram: The Sun's orbital speed is determined almost entirely by the gravitational pull ...

Figure caption, Lower diagram shows spectrum of light redshifted from a distant galaxy moving away from the Earth The upper diagram shows the absorption spectrum from a stationary galaxy with one ...

Scientists have since worked hard to pinpoint how fast the Universe is expanding, and how long ago the Big Bang took place. It’s a compelling tale, with lots of twists and turns. But ...

Nobel laureate Dr. James Peebles will discuss the still-unanswered questions regarding the expansion of the universe, dark matter and more. We have good evidence that the universe we see around us is ...