Probing the solar system

SPACE PROBES HAVE VISITED every planet in the solar system. They take photographs and gather data that cannot be collected using Earth-based equipment. Some probes fly past or orbit around planets or moons, while others land. Two Voyager space probes flew past the outer planets in the 1970s and 1980s. Two Viking spacecraft landed on Mars in 1976. The Magellan spacecraft orbited Venus from 1989 and mapped its surface. The Pathfinder spacecraft landed on Mars in 1997 and released a rover vehicle to explore the surface. The Mars Exploration Rover (MER) Mission landed two rovers in 2003. The Cassini space probe reached Saturn in 2004, and in 2005 its mini probe, Huygens, landed on one of its moons, Titan, and became the first probe to land on a moon of
another planet.

Space telescope

SPACE TELESCOPES ORBIT THE EARTH hundreds of miles above the ground, their instruments collecting light from stars and galaxies. Telescopes in space have a clearer view than those on Earth, because they are unaffected by the Earth’s atmosphere, which absorbs or distorts much of this radiation. There are a variety of types of space telescope designed to observe different types of light.
The Hubble Space Telescope observes infrared, ultraviolet, and visible light. It can detect objects that are 100 times fainter than those any telescopes on Earth can see. When this 12-ton (11,000-kilogram), 43-foot (13-meter) long telescope was launched by the Space Shuttle in 1990, it was found that its primary mirror was faulty and its images were blurred. Astronauts fitted extra optics to correct the problem in 1993.

High-performance microscopes

OPTICAL MICROSCOPES FORM A MAGNIFIED image by using lenses to bend light. Some special-purpose optical microscopes used in industry and research are designed for observing particular materials, such as living cells. They produce magnifications of up to about 2,000. Electron microscopes produce magnifications of as much as 50 million, although 2 million is more typical. Their images are formed by means of electrons focused by magnetic lenses. There are two main types: scanning electron microscopes (SEMs) scan electrons back and forth across the surface of a specimen; transmission electron microscopes (TEMs) transmit electrons through a thin slice of the specimen.

Robots

ROBOTS ARE nMACHINES THAT CAN carry out a variety of tasks on their own, with little or no human control. Most robots are mechanical arms used to build things in factories. The end of the robot’s arm can be equipped with different tools for gripping, drilling, cutting, welding, and painting. Robot toys have become popular, too. They incorporate sensors that respond to sounds and sometimes touch. Some of them can even understand spoken words. Scientists are also trying to create more advanced, humanlike robots that can see, hear, learn, and make their own decisions. ASIMO, a robot developed by the Japanese car manufacturer Honda, is one of these advanced humanoid robots. ASIMO stands for Advanced Step in Innovative MObility. It looks like a small astronaut wearing a backpack. ASIMO can walk, talk, carry things, recognize familiar faces, and respond to its name. It was the first robot that could walk independently and climb stairs. There are robot toys, too, in the shape of animals with simple artificial intelligence.

Cloning technology

IN A LIVING CELL THE GENETIC MATERIAL DNA (deoxyribonucleic acid) contains thousands of units called genes that carry instructions for development, growth, and repair of the living creature. During normal reproduction, half the mother’s genetic material contained in an egg cell joins with half the genetic material from the father carried in a sperm cell, to form a unique new genome (set of genes) for a new life. During the early stages of embryo development, the fertilized egg divides into stem cells, which have the potential to become specialized into the hundreds of cell types in a body. Through therapeutic cloning, stem cells can be produced in a laboratory. It is hoped that in the future this technology can be used to grow new tissue that can be transplanted back into the donor to treat illness, without fear of rejection— when the body recognizes a transplanted part as “foreign” because it has different genes, and tries to destroy it. In another form of cloning, performed experimentally using animals, genetic material from a donor animal has been inserted into an egg from another animal that has been emptied of its own genetic material, to produce an animal genetically identical to the donor.