From Mars to Jupiter and back

Green people will not be found there, but in the not too distant future it will be possible to answer the question of whether there is life outside the earth. Michael Shaara, head of the astrophysics department at the Natural History Museum in New York, is sure of it

  
A picture of the pole of Mars shows that it has ice on it. It is possible that in the past there was liquid water on the planet

In ten years, believes Michael Shaara, it will be possible to answer the question, if there is life outside the earth. On second thought, he talks about a period of up to 15 years, in which an answer to one of the questions that has troubled humanity for generations will be found.

"The effort," says Shaara, head of the astrophysics department at the Museum of Natural History in New York, who is responsible for the research side of the impressive planetarium that opened about two years ago, "is now directed towards the planet Mars. If there is a chance to find life, then it will be on Mars. It is a planet very similar to Earth: the temperature there is lower than the temperature on Earth, but not to a considerable extent - in the hottest place, on the hottest day, temperatures rise to 25 degrees; In the middle of the night, in the coldest place, they drop to minus 100 degrees. Moreover, there is a 24-hour day on Mars; He has power
hair. "The task will not be easy"

attraction is significant, if also weaker than on Earth; And there are signs of the presence of water on Mars, which for us is a sign of life.

"It is true that its atmosphere is different, but even if it has much less oxygen it is still not critical for the existence of life. In the first years of the existence of life on Earth, oxygen was not free and the available amounts of oxygen were less, yet primitive life existed here."
The legends about green people living on Mars are completely dismissed by Shaara. "All scientific findings show that there is no such thing. A human cannot exist on Mars, but another organism can. It can be estimated that even if life is found, it will not be more complex than a bacterium or a virus. If a more complex organism is found, it will be a big surprise."

Shaara serves as the chief professional advisor to a team of a hundred scientists, production people, graphic artists and computer people who are currently putting on a beautiful star show, the last word in the field of research, at the New York Planetarium, about extraterrestrial life.
The findings are the fruit of a year's work and include NASA photographs, including photographs from the Pathfinder spacecraft and the Hubble Space Telescope.

The impressive XNUMXD show, accompanied by a narration by the film actor Harrison Ford, takes the viewer on a journey through the stars in almost simulator conditions and presents the main points of the latest research in simple language that both adults and children can understand. Within minutes jump from Earth to Mars, and from there to Jupiter and its moon Europa, leave the Milky Way and even watch the birth of stars.

New York's renovated planetarium opened about two years ago, after 210 million dollars were invested in it. But this museum is not just a business for children. Part of it is a scientific research institute in which about 200 scientists work and students study there for master's, third and post-doctoral degrees.

According to Shaara, when researchers look for space in the universe they focus on finding water on stars. "Water", he says, "is the most important element for life and without it organisms will not exist. In the past, we also thought that the sun and oxygen were the only source of life, but we discovered, for example, bacteria that can live without oxygen, which actually kills them. The assumption that the sun is essential for the creation of life has also been falsified. We discovered in the depths of the sea that there are organisms that can exist in the dark and they get energy and nutrients from volcanic eruptions at the bottom of the oceans. It is also possible that there are organisms living on other planets that require something other than water, for example, ammonia or methane. But we have to start from some starting point."

In the next decade, Shaara adds, satellites will be sent and then laboratories manned by humans or robots that will bring samples from Mars. "We will be able to bring stones, water and maybe life from Mars. There is no clear plan yet, but it will happen sometime between the next 10 and 15 years."

However, he says, the mission to Mars will not be simple. "To reach life's potential, it will be necessary to dig. Water does not exist on the surface of Mars, but inside it. The atmospheric pressure on Mars is low compared to Earth, and when water appears on the surface of Mars it causes its immediate evaporation and freezing. We expect that at a depth of one meter to 100 meters we will be able to find rivers of water and maybe there will be bacteria or more complicated organisms in them."

Another indication that there may be life on Mars comes from a meteorite that was found in Antarctica in 1994 and researchers estimate that it came from Mars. The meteorite is billions of years old. "The meteorite remained in space for thousands of years and then fell to Earth. Inside it were small pieces of magnetic material that is similar to the magnetic material found inside bacteria on Earth, but the size of the grains was much smaller. Such size and type of grains are not found in bacteria on earth.
In our estimation the meteorite came from Mars because the isotope ratios on it are different from any stone on Earth and it is similar to what we estimate to be on Mars. This find ignites the imagination. And this means that there may be bacteria on Mars."

Even if you find bacteria on Mars, is the financial and research effort worth it?

"If we find life on Mars, even primitive life, this means that we will find at least simple life in every corner of the universe. And what we learn from the theory of evolution is that every form of life that exists develops in the direction of complexity and intelligence so that this finding will not be the end of the matter. If we don't find life on Mars, it means for us that life is a rare thing and what is happening on Earth is unusual compared to the entire universe."

Where else is the scientific community looking for life?

"The next place we look for life is on a moon of Jupiter called Europa. The advantage Europa has over Mars is that this entire moon is sea. This sea is covered with a large layer of ice tens of kilometers thick. The challenge is to try and reach Europe and dig to a depth of even 100 kilometers. So, we believe, there is a big ocean out there. The temperature of the water can be similar to the temperature of the water at the bottom of the Earth's oceans, which is a vast area for life.

"There is indeed a problem of darkness at the bottom of the oceans, but despite this, life can still exist. This is how we found in the Pacific Ocean that there are organisms in the depth when it is dark all around. The source of the energy is small volcanic eruptions that are at the bottom of the seas and emit heat and organic matter that is used as food for organisms that live in the sea."

The problem with searching for life in Europa is that its distance is five times that of Mars from Earth, Shaara says. If the flight to Mars lasts eight months, then the flight to Jupiter lasts about five years. There are indeed plans to send a spacecraft to land on Europa, but at this point they are not real. Estimates are that this will happen in 25-20 years.

According to him, in the next two decades, man's ability to explore the vastness of the universe will increase. Thus, for example, with the help of a new space telescope called TPT it will be possible to find Earth-type planets more easily. The new telescope is expected to be launched in 2020 and will make it possible to see planets a million times better than the Hubble telescope. The telescope has a very high resolution and the ability to detect planets with low light.

Why can life only exist on planets and not on ordinary stars?

"The temperature on ordinary stars - in the coldest part of the star - reaches 2,226 degrees Celsius, which is such a high temperature that only the simplest molecules can be built at it. On the planets, the temperature is much more reasonable, and in many cases it is lower than 526 degrees, which is the condition for a chemical process to be carried out and a complex molecule to be built."

The next critical question for us, Shaara says, is whether there are other planets in the universe - apart from those that exist in our solar system - moving around suns. The answer is yes. Until 1995 we didn't know if there were planets outside our solar system. Since 1995, astrophysicists have discovered about 80 planets, most of them the size of Jupiter, and even larger than it, moving around stars similar to the Sun, which are up to 100 light years away from us. Today, a new planet is found almost every week. The 80 planets have no potential for life because, like Jupiter, they are gas giants mostly made of hydrogen and helium. However, it is possible that some of the planets that exist in the universe have conditions on which life can develop, or maybe some of the planets have moons that can have conditions for life like the moon Europa.

"But it is more important that we know that the process that builds planets like Jupiter at the same time builds planets of the Earth type. And the fact that there are many Jupiter-like planets in the universe means that there is a high chance of finding Earth-type planets. We have not discovered them until today because they are much smaller. They are a hundred times weaker in terms of their light and 300 times less than sivas in terms of their weight. That is why the gravitational effect of the planets is much weaker, and then it is more difficult to discover them from the Earth."

Shaara, who worked for 17 years at Johns Hopkins University before assuming his current position and was involved in the Hubble Space Telescope, did his doctorate at Tel Aviv University between 1977-1973 with Prof. Giora Shabib, who now works at the Technion. He speaks fluent Hebrew and continues to visit Israel almost every year.

Isn't the fact that you put a lot of effort into a planetarium that provides scientific entertainment for the masses a waste of time for a scientist?

"In the last ten years there has been a change in the attitude of the community of scientists in our field towards the general public. Today there is an understanding in the astrophysics community that it is important to invest in the education of the general public. The level of understanding of science in the United States is not good and is going down. Increasing interest in our world and the universe can increase the general public's interest in physics and mathematics. Besides, we must not forget that whoever finances a significant part of the research in the field of astrophysics is the taxpayer, and we must give him something in return."

Haim Handwacker, Haaretz, New York