One of the big questions in cosmology regards the shape of the universe. “Shape” in this case is not the distribution of galaxies, but rather the shape of space and time itself. In general relativity, space and time can be warped by masses (producing the effect of gravity), and it can be warped by dark energy (producing cosmic expansion). Knowing the shape of the cosmos lets us determine if it is finite in size or infinite, and whether it will expand forever or collapse back upon itself.
Cold Comfort
The cosmic microwave background (CMB) is the thermal afterglow of the primordial fireball we call the big bang. One of the striking features of the CMB is how remarkably uniform it is. Still, there are some small variations in temperature at various points in the sky. This is actually expected, and in fact the scale at which these fluctuations occur tells us a great deal about the structure of the universe. But there is also a fluctuation that isn’t expected, and its cause is a bit of a mystery. It is known as the CMB cold spot, and there has been much speculation as to its cause.
Three Peaks at the Big Bang
One of the big points of evidence in support of the big bang is the cosmic microwave background (CMB). It is often described as the afterglow of the primordial fireball, but it is much more than that. As we make better observations of the CMB we not only gather evidence of the origin of the universe, we also get an indication of the specific nature of our universe. One of the ways we see this is through what’s known as the three peaks.
Anomalous Anomalies
When objects get hot, they give off light. You can notice this with glowing coals, incandescent light bulbs and the like. It turns out the light a hot object gives off follows a specific pattern known as a blackbody spectrum. If you look at the intensity of a blackbody spectrum as a function of its color (or wavelength), you notice shape of the function depends on the temperature of the object giving off light.
Dying Light
Photons are massless. We know they are massless because particles with mass can’t move at the speed of light. We know that special relativity works, and the speed of light is the same in all frames of reference, and special relativity only works if photons are massless. Except…
Slow Down, You Move Too Fast
The cosmic microwave background (CMB) is the faint glow of the primordial fireball known as the big bang. It is often portrayed as existing at the most distant edge of the observable universe, but in fact the entire universe is filled with a sea of photons from the CMB. These photons interact with objects in the universe. In some cases they can interact quite strongly.
Loop de Loop
Last month research project known as BICEP2 announced evidence of inflation within the cosmic microwave background (CMB). Now a new paper argues that a different effect known as a radio loop could produce similar results, which raises the question of whether inflation was detected after all.
Beyond the Sea of Stars
For generations humans looked up at the night sky and had only questions. Now we can look up at the night sky and know. Not just what stars and planets are, but the whole sky, the universe in its entirety. And yet there are still more questions to be asked.
To the Point
Popular science loves to portray the big bang as an explosion from a point. It was even portrayed this way in the new Cosmos series. The only problem is that isn’t how the universe began, and portraying it this way raises all sorts of misconceptions.