Another little blurb from PBS's website regarding Stephen Hawking's Universe:

The explosive beginning of our universe, the Big Bang marks the earliest time we can probe with current physical theory. Theory has to guide our understanding of the first fraction of a second, since we can’t recreate the extremely high temperatures that existed during the earliest history of the universe in any earthly laboratory. What theory tells us is that from an initial state in which matter and radiation are both in an extremely hot and dense form, the universe expands and the matter cools. At that time, it is believed that all four of the fundamental forces of nature—gravity, electromagnetism, and the strong and weak nuclear forces—were unified.

The evolution of the earliest universe is not well understood because it is not clear exactly what laws were at work. However, it is known that by the end of the first second of time, the building blocks of matter had formed. By the end of the first three minutes, helium and other light nuclei (like deuterium) had formed but for a long time, temperatures remained too high for the formation of most atoms. At around one million years following the Big Bang, nuclei and electrons were at low enough temperatures to coalesce to form atoms. But the universe didn’t start to look like it does today until small perturbations in the matter distribution were able to condense to form the stars and galaxies we know today.

I learned some stuff, too.

Yes. The current consensus of cosmologists postulate this theory to be most supported by the evidence.

I think when we were in school they were teaching the universe was infinite, but they have since revised their theories and now believe the universe to be finite. Meaning there is an "edge" to the universe.

It is covered in the article but I will paste it here so you don't have to search for it.

Hubble's law expansion

Main article: Hubble's law

Observations of distant galaxies and quasars show that these objects are redshifted—the light emitted from them has been shifted to longer wavelengths. This is seen by taking a frequency spectrum of the objects and then matching the spectroscopic pattern of emission lines or absorption lines corresponding to atoms of the chemical elements interacting with the light. From this analysis, a redshift can be measured. If this is interpreted as a Doppler shift we can calculate the recessional velocity. For some galaxies, it is possible to estimate distances via the cosmic distance ladder. When the recessional velocities are plotted against these distances, a linear relationship, known as Hubble's law, is observed:

where

v is the recessional velocity of the galaxy or other distant object

D is the distance to the object and

H₀ is Hubble's constant, measured to be (70 +2.4/-3.2) km/s/Mpc by the WMAP probe.^[22]

Hubble's law has two possible explanations, one of which—that we are at the center of an explosion of galaxies—is untenable given the Copernican principle. The other explanation is that the universe is uniformly expanding everywhere. This universal expansion was considered mathematically in the context of general relativity well before Hubble made his analysis and observations, and it remains the cornerstone of the Big Bang theory as developed by Friedmann, Lemaître, Robertson and Walker.

The theory requires the relation v = HD to hold at all times, where D is the proper distance, v = dD / dt, and v, H, and D all vary as the universe expands (hence we write H₀ to denote the present-day Hubble "constant&quot. For distances much smaller than the size of the observable universe, the Hubble redshift can be thought of as the Doppler shift corresponding to the recession velocity v. However, the redshift is not a true Doppler shift, but rather the result of the expansion of the universe between the time the light was emitted and the time that it was detected.

The relation between redshift and distance is more complicated than the simple relation for velocity, for it depends on past behavior of H and thus the detailed content (matter, dark energy etc.) of the model. Also, in practice, the proper distance between two objects at a given time is not measurable, and so the redshift-distance relation also depends on the operational definition of "distance" that is chosen. By coincidence, the redshift-luminosity distance relation for ΛCDM is reasonably linear to high redshift.