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 ...

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 ...

An illustration of galaxies curving the fabric of space-time in an expanding universe. A new theoretical paper proposes that cosmic expansion may not be a given — it can abruptly reverse and ...