Theory 40 Years in Astronomy: Astronomy During Last 40 Years

By the 1970's end, astronomy was nearly similar to that of today. The Big Bang theory was mostly accepted as planets were well known due to terrestrial observations and the 1960's probes. Frontiers of knowledge were already extending to the farthest galaxies and galaxy clusters. For someone who would have ceased its interest in astronomy about 1980 and would be back about 2000 what might the news be?

Planets and their worlds are now better known. The Pioneers and Voyagers craft have explored Jupiter and Saturn, those gas giants, giving the first closeup pictures of these planets and showing their moons in detail, as Uranus and Neptune which were far away worlds, became too better known. Probes sensors crossed Venus clouds as Mars has been thorougfully studied from orbit and by landers. Mars is now where life's tracks are searched for

The stars' life cycle is now better seen in its imbrications. Stars are forming in huge clouds of gas, like the famous Eagle Nebula imaged by the Hubble Space Telescope, with its towers of dark gas. This gas is hydrogen. After stars have been born in the cloud, their radiation, under the form of ultraviolet light and of matter, is eroding the gas cloud, letting behind just densest clumps of the cloud. Star formation proper occurs when a part of the gas cloud collapses under its own gravity. Most of the time a forming star is left with a disk of debris that may form a planetary system. Matter, in such protoplanetary disks, gradually collects into clumps that eventually become planets. Star formation often occurs for several stars at a time. When stars explode as supernovae they are giving birth to the heavy elements and aminated acides which planets and life are forming from, along with that they are carving the gas and dust clouds and, through the shockwaves they spread, that they are triggering the further collapse of the material and the following formation of other stars

As far as galaxies are concerned, first stars, galaxies and galaxy clusters formed earlier than thought and then evolved to progressively yield the Universe as we know it today. Such studies into the far Universe were made possible through gravitational lensing which allow to see farthest deep space objects, and through infrared studies allowing to see faintest, dust-shrouded objects. Most galaxies have a gigantic black hole in their center, some yielding large galactic polar jets due to matter accreting unto them. On the other hand, galaxies' collisions -hence star formation- accounted for a large part of galaxies evolution

In terms of cosmology, the Big Bang model kept improved by observation. Some disharmonies brought to the concepts of inflation theory, the dark matter, and the dark energy. The idea that a sudden increase of size occurred in the first times of the Universe may make easier the solution of some cosmological riddles and produces this new, fine view that the Universe is a vast filamentary net, at intersections of which the large galaxy clusters are found. The search for the weight budget of the Universe led to this idea that some invisible form of matter -what came to be called dark matter- accounts for about 25 percent of the Universe. Such a material is yet unknown and mostly unseen. At last, the recent acknowledgment that the Universe had its expansion accelerated about 7 billion years ago has been ascribed to what is called the dark energy, nature of which is still badly known too

As far as the future is concerned, next science about the solar system will be the search for life, like at Mars and at Jupiter icy moons, as the science work about the Universe will mostly use next generation, infrared tools to probe the early Universe. This will allow to understand how all the major structures of the Universe formed and fitted together, as at the same time this will allow to search for life building blocks in dust clouds, protoplanetary disks, down to the exoplanets