P1bL14 In the Beginning

Key Words

Background radiation - microwave radiation in space

Big Bang - the cataclysmic explosion in which the universe was formed.

Electrons - tiny particles with negative charge.

Neutrons - particles found in the nucleus that have the same mass as a proton, but have zero charge.

Protons - particles found in the nucleus that have a positive charge.

Test Yourself

Homework
Physics GCSE
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Grade E

Astronomers have observed that stars and galaxies are moving away from us.  Therefore they believe that everything was once contained in one place.  All the matter in the universe was contained as energy in the space of a pinhead.

The energy was released in an enormous explosion called the Big Bang.  The temperature was billions of Kelvin.  Then within seconds, some of the energy turned into matter, making electrons, protons, and neutrons.  These in turn started to make the simple atoms like Hydrogen (1 proton and 1 electron).

 

Grade C

A strange fact of Physics is that energy can be turned into matter and matter back into energy.  It is governed by Einstein's simple but classic equation:

Energy (J) = mass (kg) × (speed of light (m/s))2

In Physics Code:

E = mc2

In the massively high temperatures of the Big Bang (1032 K), a whole zoo of particles was made, for example:

  • electrons;

  • quarks;

  • neutrinos;

  • photons;

  • matter;

  • anti-matter.

Particle Physicists are using massive machines to produce the conditions after the Big Bang.  They have got within 10-30 s after the Big Bang.

Conditions cooled rapidly after the Big Bang.  After 15 000 million years, the temperature of Outer Space is 3 Kelvin (-270 oC), not very warm.

 

Grade A

Light travels at 300 million m/s.  It takes 8 minutes for the light of the Sun to get to us.  The nearest star other than the Sun is 4 light years away.  A light year is the distance that light travels in 1 year, which is about 1016 m.  So the light that left that star did so in 2004.  If the star went out now, we wouldn't know about it for 4 years.

Light from distant galaxies takes thousands of millions of years to get to us.  Therefore we can say that what we see now is what the galaxies were like all that time ago.  Many of them might well not exist now.

Cosmic background radiation has also been discovered, which is considered to be the afterglow of the Big Bang.

Do not confuse cosmic background radiation with the background radiation you measure when doing radioactivity experiments.