The number of people from the planet has been reduced drastically in the latter by 70,000 years, and the human race has been threatened with disappearance. An extensive genetic study shows that, because of the drought, in that time people lived in small groups and isolated in Africa, the total number of people was only of 2,000 individuals.
70,000 years ago , people lived in small groups and isolated. East Africa has been passive to a hard drought ago 135.000-90.000 years and climatic conditions probably have produced changes in the number and type of men organization.
Researchers have reached these conclusions after having analysed the genetic material of some populations of southern Africa. "The study shows the extraordinary power of genetics to remove some light on key events for our species," said Sepncer Wells, a researcher of the National Geographic Society.
Today, around the world live more than 6.6 billion people.
According To A Study The Human Race Was Near Extinction
It Was Discovered The Smallest Black Hole
Two NASA scientists have found black hole least bulk. This is only 3.8 times more massive than our sun. How its mass is very close to the bottom theoretical limit of 1.4 solar masses for black holes, understand why the search for black holes all less massive represents a test of our theory about stars constitution.
Black holes have fascinated the people imagination since they were predict by the Einstein theory of general relativity. He himself is not believed ever will be discovered. However, now known many candidates to the title of "black hole" that physicists no longer doubt of their reality. It seems that in the center of each galaxies are a black hole. Also, massive stars after their nuclear fuel is consumed under the influence of gravity, crash becoming a powerful black hole. However, not every star can become a black hole, but only those which have mass of approximately 1.4 times greater than the mass of our Sun. If a star has a mass less than the limit, it may remain a White Dwarf, or can become a neutron star. The neutron stars are the most dense bodies in the Universe after the black holes.
We understand therefore why the experimental detection of black holes with masses less than everything is very important. It is a direct test of the Chandrasekhar limit, which in turn comes from our current understanding of matter star. The lowest black hole known currently has a mass of only 3.8 times greater than our Sun.
The black hole that had until now what the record is the least massive black hole is called GRO 1655-40 and has about 6.3 solar masses. Black hole discovered now is named J1650, has about 3.8 solar masses, with an uncertainty of approximately 0.5 solar masses and has a diameter of only 24 kilometers (as a small town). J1650 is in our galaxy.