What are the conditions for life ?
When the first distant planets were discovered, one had to realize that they are gas giants, about as big as Jupiter. Jupiter is by far the largest planet in our solar system; and furthermore, some astronomers have discovered and, of course, also proved so-called Super Earths. They are derived from our Earth, only they are incredibly large. They have about 10 times the mass of Earth……..almost unimaginable, right?
Discovering all this naturally leads to further foreseeable questions?
What about life? …namely : Such a life as we of course already know it and the conditions we know best must be fulfilled.
The planet must be made of rock only. Because it is also certain that rock can only form in the mass range of the Super Earths.
Decisive is the distance to the respective star. Also known is the habitable zone, which means nothing else than that in which life is possible on a planet, varies according to the size and luminosity of the respective star. I notice: a radiated heat of a star decreases with increasing distance.
Furthermore, it is very important that the temperature on the planet is necessarily between zero and one hundred degrees. The presence of water is only possible under these conditions.
What is known, a first exoplanet of rock discovered by astronomers is called Kepler 10b. However, this planet orbits so close to its star that temperatures of up to 1,500 degrees Celsius prevail on it.
When is life possible? What do we need to know?
Which factors can be measured quite reliably today? It is the distance of a planet to its star, its mass and of course its size. But what could not be measured so easily was a statement about the nature or structure of the planet. What exactly was she doing? I will try to explain it. Actually, something very plausible. She breaks down the starlight of the planets into its components and examines it in detail. …because starlight consists of a spectrum of light with different wavelengths. So if a discovered planet has a certain atmosphere, the molecules in that atmosphere absorb the light waves from its star. The planet, as we know, passes in front of its star, so its atmosphere filters certain wavelengths out of the starlight. This „filtering“ creates, ….. Let’s call it, a „spectral fingerprint“. So again, it creates an individual spectral fingerprint of the planet’s atmosphere.
So Lisa Kaltenegger is developing, and this is an outstanding achievement, analytical models for the atmospheres of distant exoplanets.
The light can „talk“, it is filtered by a planet’s atmosphere or reflected from a planet, then it tells us which chemicals – e.g. water, oxygen, methane, carbon dioxide – are contained in the atmosphere of such a planet. So it tells us whether the Earth has a similar atmosphere or whether it is completely different. Simply said, the observed atmosphere of an exoplanet is compared with the atmosphere of the earth and therefore we get the gladly expected information, on this celestial body life is possible…….or also as so far explored, not.!!!!!!!!!!
What else will be in the shopping basket of our future scientific research ? It will be a matter of time. Generations of researchers (astronomers) will have to donate enough effort to be successful……..I do not see any exoplanets with human life
Which atmospheres have astronomers looked at so far? They are almost only the atmospheres of „giant“ planets……but pure „gas planets“, that’s how it is. One immediately encounters a problem in the measurements; this becomes apparent when one looks at the proportions of the atmospheres and the planets. For simplicity, let’s look at the atmosphere of the Earth.
It is about one hundred kilometres high and the radius of the Earth is over 6,000 kilometres. It can be represented in the shape of… …an apple. So it’s just a very thin skin, the thin atmosphere, it’s comparable to the skin of an apple. The planet is the apple, the thin peel is all the information about the atmosphere!
And what can be imagined, they, these „shells“ are by no means always several light years away.
We have to use large telescopes to collect so much light that we can observe even the smallest planets. This is the only way to carry out a productive search for traces in space. Planned and known how, then done.
So they planned the Extra Large Telescope“ (E-ELT) in Chile and also
the „James Webb“ space telescope, which is due to be launched in 2018. (thinking)
The James Webb Space Telescope (James Webb Space Telescope, abbreviated JWST) is a space telescope as a joint project of the space agencies NASA, ESA and CSA to be launched in 2021. Of course everything begins with a name. The chosen name was first : Next Generation Space Telescope but by 2002 a new name had been found. It was decided to name it James Webb Telescope, a former NASA administrator.
The new telescope is a successor to the well known Hubble telescope. But it certainly does not need to be mentioned, of course it should exceed the performance of its predecessor. The Hubble telescope worked in the visible, near, ultraviolet and near infrared spectrum. Now JWST is said to be used almost exclusively for infrared astronomy. A few details :
Total mass of the telescope at launch, including fuel, is approximately 6.2 tons. The final station will be about 1.5 million km from Earth. Of course on the side away from the sun at the so-called Lagrange point L2 of the Earth-Sun system.
Which scientifically relevant tasks are in the foreground for the JWST ?
It will search for light from the first stars and galaxies and the Big Bang.
In general, the structure and evolution of galaxies will be investigated.
It is hoped that the understanding of the structure of stars and planetary systems will be expanded.
…….and at the top of the list will be the study of planetary systems and their suitability for „life“.
Before I lose myself in the confusion, some facts which are still firm today.
⁃ the JWST will work with the 0.6-28 µm frequency spectrum of infrared light.
⁃ After arrival in orbit and a preparation time of six months most of the scientific projects will probably start with the telescope, which will occupy it for „five“ years in the currently planned scope. But an enormous expansion of the scientific tasks to „ten“ years is planned.
Now an almost never ending topic : financing and start date
The original launch was planned for 2014 with an Ariane 5. According to official figures, the necessary EUR 3.3 billion had been secured on the US side for the construction and ten years of operation. Now the word „miscalculated“ came up. The costs made an enormous leap and as always usual with projects of this kind it was said on July 13, 2011. The construction of the telescope is stopped !
NASA estimated the construction costs at that time at 8.7 billion dollars. And how it almost always goes like this In December 2014 the financing including operating costs of the first five years was again considered to be secured. Now of course the launch had to be redefined. To a new 2018. ?
Many words with little sense……..after several additional postponements, technical problems and certain still outstanding final productions ……
…….another postponement to March 2021 at the earliest. And as you would expect, the total costs are now about 9.66 billion dollars of which pure development costs are certainly 8.8 billion dollars.
The expectations of all involved are high and may be. Of course „Lisa Kaltenegger“ also has high hopes: Because in our galaxy there are billions of stars. And one can assume that if every star, every second one, has at least one planet, then we already have billions of planets in our Milky Way, that is, in our galaxy alone. Further without „consideration of losses“, there are still billions of galaxies out there. That means, if you extrapolate, it should be quite exciting in the near future.
Part 6 follows… …then that‘s is the end