The Second Morning: Heavy Elements
Gravity gathered the expanding gas of the second evening into clouds and contracted the clouds into the first galaxies and stars. The gravitational energy of the matter falling into the denser regions heated them up again until they began to emit light. One of the regions became the galaxy now called the Milky Way. Primitive stars formed, and the second morning began.
We cannot see the origin of our own galaxy, because we are inside it. However, the Hubble Space Telescope and the Keck Telescope on Mauna Kea, Hawaii, have photographed some of the most distant galaxies. These are also the earliest, because light takes the longest time to come to us from them. Beyond them (and therefore preceding them in time) there is darkness. The darkness is the end of the second evening and the light of each galaxy is the dawn of the second morning for that galaxy.
We cannot see the origin of our own galaxy, because we are inside it. However, the Hubble Space Telescope and the Keck Telescope on Mauna Kea, Hawaii, have photographed some of the most distant galaxies. These are also the earliest, because light takes the longest time to come to us from them. Beyond them (and therefore preceding them in time) there is darkness. The darkness is the end of the second evening and the light of each galaxy is the dawn of the second morning for that galaxy.
A primitive galaxy shines red in the second morning against the backdrop of the second evening.
Heat and Light Make Heavy Elements
In the second morning, random collisions between hydrogen, helium, and lithium nuclei formed all 92 of the natural elements in the centers of stars.
The high temperature and pressure of the first three minutes did not last long enough to make the more complex kinds of atoms. Stripping the first atoms of their electrons and cooking their lightweight nuclei into heavy nuclei at high temperature and pressure needed another cycle of darkness and light lasting thousands of millions of years. How the first stars did that is also a great discovery of the 20th century. It is the synthesis of the heavy elements.
The principal fuel available to power the first stars was hydrogen. Besides making light and heat, nuclear reactions consume hydrogen to make helium and heavier elements.
In the second morning, random collisions between hydrogen, helium, and lithium nuclei formed all 92 of the natural elements in the centers of stars.
The high temperature and pressure of the first three minutes did not last long enough to make the more complex kinds of atoms. Stripping the first atoms of their electrons and cooking their lightweight nuclei into heavy nuclei at high temperature and pressure needed another cycle of darkness and light lasting thousands of millions of years. How the first stars did that is also a great discovery of the 20th century. It is the synthesis of the heavy elements.
The principal fuel available to power the first stars was hydrogen. Besides making light and heat, nuclear reactions consume hydrogen to make helium and heavier elements.