Antarctica is the best place on Earth to search for meteorites. 4,750 of them have already been found here, which is more than 60% of the world’s collections. And these numbers are growing rapidly. Of course, meteorites do not fall in Antarctica more often than anywhere else. Catching a fall and picking up a “fresh one” is almost an incredible stroke of luck. And such a trophy is much easier to find on the ice continent than on any other.
The radio telescope at the Amundsen-Scott station. Photo: UNIVERSITY OF CHICAGO
The ice shell itself works as a giant meteorite delivery line. A stone that has fallen from the sky gets stuck in local glaciers. But the ice does not remain motionless, it slowly flows down from the hills into the lowlands. The ice accumulating in the traps gradually evaporates under the pressure of strong Antarctic winds. But meteorites accumulated over millions of years remain, and scientists are hunting for them.
Some meteorites are fragments of asteroids. Occasionally there are visitors from the Moon and Mars. But most of the celestial stones are construction debris from the time of the formation of planets, which never became part of large bodies. They are older than the Earth, and sometimes there are inclusions in them that are older than the Sun itself. Thanks to them, we can study the building material of the Solar System almost in its original form.
Elusive neutrinos
Meteorites are not the only thing raining down on Antarctica from the sky. A grandiose cosmic neutrino detector (IceCube) has been built at the Amundsen-Scott station located at the South Pole. It uses an entire cubic kilometer of ice at a depth of 1.5 to 2.5 km. There are 5,160 sensors scattered around this cube. They record flashes of light accompanying the visits of space visitors.
Neutrinos are very light particles that have no electric charge. They almost never interact with ordinary matter, as if they consider it beneath their dignity. Therefore, neutrinos pierce the thickness of planets and stars, unchanged (read unharmed) passing through any obstacles. They bring us news from the bowels of the Earth, the center of the Sun and the vicinity of black holes.
There are different types of neutrinos, but the IceCube telescope is aimed only at ultrahigh-energy neutrinos coming from space. Real cosmic neutrinos are a piece—by-piece product. The most energetic of them are recorded several times a year, and then only due to the huge volume of the installation. It is clear why IceCube is located in Antarctica: where else can I find a cubic kilometer of eternal ice?
The unique instrument has already lifted the veil of mystery over the origin of ultrahigh-energy cosmic neutrinos. At least some of them come from supermassive black holes in the centers of galaxies. But it remains a mystery how they form there and whether there are other sources of similar particles in space.
The Echo of the Big Bang
The world’s southernmost radio telescope operates at the same Amundsen-Scott station. Without further ado, the creators called it the South Polar Telescope. Radio telescopes pick up radio waves coming to Earth from space. The sources of these waves are diverse: These are neutron stars, galactic nuclei, interstellar gas, and so on.
Why was it necessary to build the SPT at the South Pole? The fact is that it operates at a wavelength of 1-4 mm. Such waves are strongly absorbed by water vapor. And in Antarctica, and even at an altitude of 2800 m above sea level, the air is clean and very dry. And there’s also a very phlegmatic Sun: it doesn’t set or rise for months.
The main object of study for the Antarctic telescope is the cosmic microwave background radiation. It has been traveling through space since the time of the Big Bang. The newborn universe was very hot. Matter and radiation were mixed up, and photons kept bumping into particles of matter. But space expanded rapidly, energy was distributed over an increasing volume, and matter cooled.
About 300,000 years after the Big Bang, the cosmic microwave background radiation finally separated from matter. But it still retains traces of a stormy youth. By studying the “relic”, one can understand how rapidly the universe expanded in the first moments of life and what particles photons encountered then. Among them may be, for example, particles of dark matter, still unknown to science.
Cosmic rays
Cosmic ray detector at Mawson Station. Photo: PETER LAYT
Our planet is a cosmic phenomenon in itself. It has a complex relationship with the fluxes of particles and radiation from the Sun and from deep space. The invisible arches of the Earth’s magnetic field extend far beyond the atmosphere. But at the magnetic poles, they go under the surface of the planet. By the way, the magnetic poles do not coincide with the geographical ones and, moreover, they are constantly drifting.
The magnetic field protects us from the solar wind — protons and electrons continuously flowing out of the Sun. These particles, trapped in the geomagnetic shield, repeatedly fly along the magnetic lines and bounce off the field thickenings at the poles. But during magnetic storms, the polar “magnetic plugs” give holes. Then the particles penetrate the atmosphere and cause auroras.
Near the poles, where geomagnetic lines invade directly into the ionosphere and descend to the surface, various geophysical phenomena are observed that are never seen in the middle latitudes. Cosmic rays, charged particles coming from the depths of galaxies, add diversity. The plasma of the solar wind, the geomagnetic field, and the atmosphere are all obstacles in the path of cosmic rays.
Unlike the elusive neutrinos, these visitors from deep space never reach the Earth’s surface: they collide with air atoms and generate showers of secondary particles. In the northern regions, where there is practically “its own atmosphere”, this space hurdling can also look like an aurora borealis.
In general, Antarctica, like the Arctic, is a natural laboratory for studying the connections between Earth and space. Many Antarctic stations (for example, the Russian stations Mirny, Vostok, Novolazarevskaya) monitor the state of the ionosphere and the geomagnetic field. And the largest cosmic ray detector in Antarctica is located at the Australian Mawson Station.
Like on Mars
Researchers have another reason to be interested in Antarctica. This is the most Mars-like corner of the Earth. It is cold on the red planet: even at the equator, the average annual temperature is below -40 °C. But this will not surprise the polar explorers from the Vostok station, where it is below -55 ° C. The Vostok weather station recorded the lowest air temperature on Earth in the entire history of observations: -89.2 °C.
Not only space technology is being tested on the icy continent, but also “space people”. Back in the 1960s and 1970s, long space flights were simulated at the Vostok station. For nine months of the year, the “East” is cut off from the outside world. Polar explorers, like astronauts, have to rely on themselves in any situation.
Going outside the station is like going into outer space: terrifying temperatures, the pitch darkness of the polar night, or the glare of the setting sun burning unprotected eyes. Moreover, there is little oxygen in the air: after all, almost three and a half kilometers above sea level. Nevertheless, the main test is long isolation in a confined space.
The Antarctic pioneers were attracted by the same passions as the space explorers. Audacity, the desire to go beyond the usual boundaries, thirst for knowledge. It is said that George Mallory, when asked why he wanted to climb Mount Everest, replied: “Because it exists.” Perhaps this is the most honest answer to why a person stubbornly rushes to the most inhospitable corners of the planet and beyond.
By Anatoly Glossev
