Do we really know everything about the universe?

Even though we don’t know everything, there are enormous sources of knowledge that have empowered us to draw far-reaching conclusions about our Universe. We know what it’s made up of in terms of matter, energy, radiation and so on.

What happened to the universe after the Big Bang?

The universe carried on expanding and cooling, but at a fraction of the initial rate. For the next 380,000 years, the Universe was so dense that not even light could move through it – the cosmos was an opaque, superhot plasma of scattered particles.

How did the universe become the lumpy entity we see today?

Radiation burst out in every direction, and the Universe was on its way to becoming the lumpy entity we see today, with vast swaths of empty space punctuated by clumps of particles, dust, stars, black holes, galaxies, radiation, and other forms of matter and energy.

Why doesn’t the universe appear curved?

The Big Bang, on its own, offers no explanation as to why the initial expansion rate at the moment of the Universe’s birth balances the total energy density so perfectly, leaving no room for spatial curvature at all. Our Universe appears perfectly spatially flat.

Is the Big Bang a valid explanation of the universe?

The full suite of data, including the observations of the light elements and the cosmic microwave background, leaves only the Big Bang as a valid explanation for all we see. As the Universe expands, it also cools, enabling ions, neutral atoms, and eventually molecules, gas clouds, stars, and finally galaxies to form.

Is the universe expanding or cooling?

If this were the case, then the Universe should not only be expanding but cooling, as the wavelength of light would be stretched to lower and lower energies as time went on. We should see a leftover glow with particular properties dating back to the earliest times: the cosmic microwave background. We should see an evolving web of cosmic structure.