Question

1 What is the oldest point in time where life happened(call it “Time = 0”)? What evidence do we trust to figure that? What is the furthest point in time for life to exist (in other words: how would you identify a point of extinction of life)?

2 Given the same amount of time, the same materials in the same configuration as on “Time=0” above, would you expect 2019 to be “re-played” all over again if we went back to that point in time? Why, or why not?

Answer 1

Ans 1) The oldest times when life occurred for the first time is believed to be almost 3.5 years ago and this is when the origin of life is considered. The earliest evidence of life comes from the oldest rocks which are still well preserved on our planet that dates almost 4 billion years ago. The oldest evidence comes from fossil from a structure called stomatolites that resemble a microbial mat that was found in Australia. It is estimated that this structure extracted energy from sunlight and evolved gradually to form the modern day microbes. Another example of oldest form of life is cyanobacterial colonies fossil which are considered to be around 3.7 million years.

There are a lot of predictions that have been made regarding the farthest point till where life can exist. However, astrophysics has been able to help with estimating the extent till extinction comes. It states that depending on particle physics and how the planet and stars interact and tectonic plates move, it will be able to estimate the life on Earth. The extinction might come when the stars energy supply as well as their hydrogen fuel will be all exhausted. It is estimated based on astrophysics that it would take around 1 billion more years for extinction.