Prof. Amiel Sternberg from Tel Aviv University: the fossils of life on Mars should be looked for in the dry lakes
Future landing vehicle on Mars. Illustration - NASA
There is no liquid water on Mars today due to the low air pressure there, only about one percent of the air pressure on Earth. This is how Prof. Amiel Sternberg from Tel Aviv University explains. Sternberg was one of the lecturers at a study evening that took place on Tuesday this week at Tel Aviv University, under the title Space Science Man, a study evening in memory of Ilan Ramon and his Columbia team members.
At the conference, several studies being carried out at Tel Aviv University were described, among them the experiments conducted on the Columbia shuttle. The second part of the conference dealt with Mars, the Hubble telescope (Prof. Dan Maoz) and the rebuke of Prof. Hagi Netzer. Earlier, the evening was started by Prof. Zev Levin and Dr. Colin Price as well as Lt. Col. (retd) Yitzhak Mayo - all of them participated in the Israeli MEIDEX experiment carried out with the help of the space shuttle Columbia. We will get to their comments in the coming week in separate news.
And if we go back to Mars, today there is low air pressure in the atmosphere, and most of it is composed of carbon dioxide. At such air pressure, water does not boil at XNUMX degrees as at sea level on Earth, but at XNUMX degrees Celsius. Thus water can be found in abundance in the form of ice at the poles or in the form of vapor in the few clouds scattered here and there. According to Sternberg, photographs of Mars show that although Mars has been a dead planet for billions of years, there were periods of several million years when there was apparently stronger air pressure, and large lakes and channels existed. On Earth, lakes that have dried up are a good place to look for fossils at the bottom of them and indeed even on Mars you have to get to these isolated places and dig in them.
Prof. Sternberg described the previous journeys to Mars and showed beautiful photographs, including a photograph of a sunset on Mars, which by the way, the sky there is never clean but there are always dust storms that reduce visibility and give Mars its red hue.
Meanwhile, the BBC website reports that the European spacecraft that will be launched to Mars in 2009 will contain a probe to dig into the Martian soil. This is a robot that will be powered by solar energy and will spend months on the surface of Mars. The robot-vehicle will be equipped with a mobile laboratory, an excavator and a system that will take soil samples from sites that can contain primitive life forms. The European Space Agency is looking for more ideas for the same mission.
This summer three spacecraft will be launched towards Mars - two American and one European. NASA will send two rovers to Mars in May and June. The identical robots will have six wheels and be able to travel about a mile a day. These vehicles are currently called Rover 1 and Rover 2, but NASA's naming contest is underway.
The European spacecraft, Mars Express will be launched in June and will carry the British landing vehicle, Beagle 2 (Beagle 1 was of course the ship in which Darwin circled the Earth in the 19s for five years and in which he conceived the theory of evolution).
The British robot was designed to parachute onto the surface of Mars and land near the border between ancient mountains and the northern plateau, around the end of the calendar year. The spacecraft will dig at its landing point and analyze the rocks for water, but it will not be able to move from the landing point.
The next opportunity to launch spacecraft to Mars will arrive in 2009 and the European Space Agency is preparing for this opportunity. The vehicle will be part of the ExoMars project to study the biology of the Red Planet and part of the European Space Agency's Aurora program designed to pave the way for future manned launches of the hostile surface of Mars.
The "Mars explorers" will cover a hundred meters a day, drill into the ground and analyze the composition of the rocks
By Stefano Colden New York Times
The patrol robots. will move a relatively large distance away from the mother spacecraft. Photo: NASA
While the engineering tests and mental calculations about the loss of the shuttle Columbia continue, the US space agency is focusing research attention on Mars. In May and June, two rover robots will be launched to the planet, and next January they are expected to land near the equator of Mars.
Both rovers resemble the smaller robot Sojourner, which landed on Mars in 1997. Images of the tiny, toy-like rover were circulated around the world almost overnight. But the Sojourner mission was mainly a technological demonstration whose scientific goals were modest. Sojourner's travels in 1997 were centered within a few meters of the Pathfinder mother spacecraft, which conducted most of the scientific research.
The new cruisers, on the other hand, can move about a kilometer away from the original landing sites. Both labs-on-wheels are being prepared for flight in a special clean room at the Kennedy Space Center. Reporters toured the site last week; Before entering, they were required to put on hoods and masks, wear suits and wear boots. All the equipment they brought was wiped with alcohol.
Each robot will carry several scientific instruments to study the Martian environment. A panoramic XNUMXD camera that is one and a half meters high will help scientists explore the landscape, select the most interesting rocks and soil and guide the explorer to the goal. Three types of spectrometers will be used to determine the composition of the findings by analyzing the radiation coming from them. Microscopic cameras will provide high-resolution images of rocks and soil.
The devices are assembled on top of the robot's arms, which also carry special drills, with which the explorers will score the outer layers of the rocks to check their internal composition. In the meantime, the robots are called Explorer 1 and Explorer 2 (their final names will be chosen in a competition to be held among school students across the US). They can be folded and stored inside a pyramid-like platform, which will be used as an access gate to the surface of Mars. The pyramid will be stored inside a cone-shaped shell, which will be equipped with a layer Protection against the great heat that will be generated upon entering the planet's atmosphere.
When the spacecraft that will carry the robots approaches Mars, parachutes will be opened and braking missiles will be launched to slow down its movement. Relatively quickly, the cone shell and the thermal protection layer will be removed one after the other. A cluster of airbags, which are twice as durable as protective vests, will inflate to absorb the energy released upon landing. The scientists predict that the first jump will jump the cluster to a height of 30 meters, and after about a dozen more jumps it will stop, about 800 meters from the initial landing site. Gradually the air will be released from the cushions, the pyramid will be turned so that its apex points upwards, and then the sides of the pyramid will open and the rover will be exposed to the thin and frozen air of Mars. Only after four to five days of testing will the patrols begin their mission.
For three months, and possibly more, the explorers will conduct research and move up to a hundred meters a day, powered by batteries that produce energy from solar panels. Since nighttime temperatures on Mars are expected to drop to minus 105 degrees Celsius, the designers equipped each robot with eight blocks of plutonium dioxide to keep the batteries and other electrical devices warm.
Alternative channels
By Duncan Steele
Mars. Most scientists believe that there was a flow of water across the planet
Photo: NASA
Mars enthusiasts would like to turn the red planet blue and green. In their dreams, green vegetation fills the arid expanses of Mars, which will be made fertile by enormous amounts of water. This water, which is now in frozen deposits below the surface of the planet, will be released from there, according to those fantasies, in a grandiose engineering project. But the realization of the dream of Mars enthusiasts is possible only if there is a sufficient amount of water on the planet and only if this water can exist in liquid form.
According to the explanation accepted by scientists - which is supported
By photographs of the Mars Global Survivor spacecraft - in the past water flowed on Mars. This happened when the temperature on the planet was higher than today. Research attention is focused on solving the question of how that warm period was created on Mars. One hypothesis is that a more compressed atmosphere made this possible; According to another hypothesis, the collision of a massive asteroid with the planet caused the warming. Either way, most scientists agree that water did flow on the surface of Mars in the past.
Dr. Nick Hoffman, a geologist at the University of Melbourne, disagrees. He examined the channels and trenches that were thought to have been created by the flowing water and developed an alternative theory. Hoffman compared the soil on Mars where the channels and trenches were cut to the soil on Earth where avalanches of boiling rocks occurred , dust and gas, caused by volcanic eruptions. According to him, the two findings are very similar to each other.
Huge volcanoes once existed on Mars, but Hoffman does not claim that the channels and canals on Mars are the result of their eruption. He is talking about a phenomenon that is perhaps reminiscent of the eruptions of the icy volcanoes that the Voyager 2 spacecraft discovered on Triton, Neptune's huge moon. In these volcanoes, jets of dust and gas spray up, apparently as a result of the evaporation of liquid nitrogen that is under the ground.
Hoffman speculates that something similar might have happened on Mars. At the low temperature on the planet, about minus 50 degrees, it is possible that the eruptions of gases will cause similar results to those of volcanic eruptions on Earth. In these eruptions, which may be short but repeated, the gas erupts causing rock and soil to be washed away, and channels to be carved into the surface of the ground.
The key chemical in such a process is carbon dioxide. On the ground surface of Mars, where the atmospheric pressure is extremely low, carbon dioxide exists only as a gas or a solid. On the other hand, underground, where the pressure is greater, it can exist as a liquid. And just as there are water deposits called aquifers under the surface of the Earth, it is possible that there are reservoirs of liquid carbon dioxide under the surface of Mars.
If those reservoirs do exist, they could explain the channels on Mars. Hoffman raises the following possibility: liquid carbon dioxide accumulates under the surface of the ground, and when the fragile ground cracks, the carbon dioxide spreads, bursts out and creates a cloud of compressed and cold gas that sweeps rocks and dust with it and carves channels in the ground.
Hoffman's theory is not acceptable to most researchers, and certainly not to those who hope to find life on Mars. It is possible that soon it will be possible to better assess the validity of the theory. In the coming months, the European Space Agency will launch the Mars Express spacecraft, and shortly thereafter NASA is scheduled to launch two space vehicles to Mars. The Japanese spacecraft Nazumi, launched in 1998, is also scheduled to reach Mars in December. Among their other missions, these spacecraft are supposed to collect data on the existence of water on the planet. If Dr. Hoffman is right, Mars would always be talking Arid, frozen and almost certainly lifeless.
