The periodic table was discovered mainly by chemists and was based on the electronic structure of the elements, as explained by Physical Chemistry. Today, new elements are discovered in high energy colliders (physics) and the most recent element discovered in 1996, is called Ununbium atomic number 112 and its most stable isotope is 285.
Guess what? It has a lifespan of 280 microseconds 0.00280 seconds. So it doesn’t stay long. Why? It has so many protons and neutrons that nuclear forces cannot hold them together.
As the atomic number increases, the elements generally become less stable. Neutrons and a lot of quantum mechanics are used to understand stability, but eventually forces of nature fail and large or radioactive elements decay into something else. Radioactivity is a hallmark of unstable elements.
Now these high atomic number elements are generally detected in high energy reactors. If that Ununbium element only lives 280 ms, that means in our frame of reference that we are stationary. In fact, in accelerators, Einstein’s relativity tells us that as particles move faster relative to us, they appear to live longer. So, from our frame, looking at them, move so fast, so that they stay longer.
All of these new elements are unstable and radioactive. They cannot play any role in life as we know it. In fact, we know all the stable elements. The Periodic Table puzzle that Dmitri Mendeleev started in 1869 is finished and we have all the pieces for the stable elements, and much more. There are no other elements except these short-lived with high atomic numbers.
The current interest is not in finding new elements, but in understanding the smallest elementary particles that form when atoms collide. The Large Hadron Collider in Europe is doing just that. One particle they are looking for is the Higgs boson.
Conditions for Life
Also, if you look with telescopes and do spectroscopy of different stars, guess what, we see the same elements as on Earth. So we can assume that the structure of matter is the same throughout our Universe and that our periodic table is the same on remote planets. They have the same chemistry. If life exists, it is most likely carbon-based, as on Earth, and similar to what we know.
You are assuming that we should seek life in the center of our Universe because it has the best time to evolve. So if time were only the only factor, he argues, there would be more life there. However, the Universe is very old: around 13 billion Earth years. That is more than enough time for evolution anywhere in the Universe as long as the conditions are correct.
Liquid water and a stable planet are needed for intelligent life to evolve. The best estimate for the evolution of humans is about 100 million years, but the life of a small cell evolves rapidly. The reason humans took longer is because we are complicated and throughout our Earth’s history, there have been mass extinctions along the way (we know of 6 such events, but there could be more).
There are many other things we need for life to develop as well: a large moon to stabilize the Earth’s axis, plate tectonics (long story), and many other conditions. For example, mass extinctions are caused by collisions with meteors or other objects. A meteor 1000 meters in diameter (that is, with a diameter 1/8000 times smaller than that of the Earth) would kill everything and boil the oceans, thus sterilizing the Earth. At 100 meters, the meteorite would kill about 60% of life. Now we get lucky again. It has been 4 billion years since we were hit by a 1000 m diameter meteor. There are two reasons for this: there are fewer such objects around (they have had 13 billion years to collide, so many have been removed). The other point is that Saturn and Jupiter are much larger than Earth and are further from the sun. Its stronger gravitational force attracts many large meteorites, so they hit to hit them before we do. Saturn and Jupiter protect us !! All these factors and many more have given us the conditions for life to evolve on a stable Earth.
We’re alone?
People generally believe that life is ubiquitous, but intelligent life may not be. So astronomers look for planets like bears. In the past, we listened to the skies for lost radio signals, to no avail. There was a time when astronomers focused on a dense collection of stars, but concluded that the radiation was too intense for life to form. Recently, the Kepler Telescope was launched in 2009 and is looking for Earth-like planets. To date, they have located more than a thousand candidates.
Of course, these planets are usually hundreds, if not more, of light years away. We can transmit radio signals to the planets, but it will be a long time before we get answers.
There are many stars and probably many more planets and a lot of life out there. On the other hand, some people believe that intelligent life is very rare because the optimal conditions for intelligent life are very unlikely. In other words, we are very lucky and we must ensure that our Earth remains healthy for us.