The 400-year-old quest for extraterrestrial life

It is, perhaps, a telling observation that the two tools that first gave human beings the ability to explore the world about them in scientific detail, at both the universal and microscopic level, were invented at about the same time. On October 2, 1608, 408 years ago, Hans Lippershey, a German-born grinder of lenses and […]

It is, perhaps, a telling observation that the two tools that first gave human beings the ability to explore the world about them in scientific detail, at both the universal and microscopic level, were invented at about the same time.

On October 2, 1608, 408 years ago, Hans Lippershey, a German-born grinder of lenses and maker of spectacles from Middelburg in The Netherlands, made the first recorded application to patent an instrument “for seeing things far away as if they were near by”.

History credits his out-patented rival Zacharias Janssen, who was from the same town and is also believed to have been working on a telescope, with the invention of the microscope instead.

As described in the documents filed with the parliament of The Hague, Lippershey’s invention was a relatively crude device. A tube of about 4 centimetres in diameter and 50cm long was fitted with a convex lens at the front and a concave lens at the eyepiece, and magnified objects fourfold.

Crude or not, in intention if not scope this was the ancestral forebear of the world’s largest single-dish radio telescope, which began operating in China this week.

The Five-hundred-metre Aperture Spherical Radio Telescope (Fast), a true wonder of the age of radio astronomy, is the latest and most advanced expression yet of mankind’s curiosity about the universe and our place in it.

Built in the mountainous region of Guizhou in southwest China at a cost of US$180 million (Dh661m), the imposing Fast employs no lenses. The most powerful terrestrial telescopes pointed at the stars today are scouring wavelengths far beyond the electromagnetic spectrum visible to the human eye. Fast is focused on a narrow band of wavelengths, between 70MHz and 3GHz, straddling very high, ultra high and super high radio frequencies.

What this means is that its 500-metre dish, twice as sensitive and up to 10 times as fast as its nearest rival, the Arecibo observatory in Puerto Rico, is perfectly positioned and attuned to collect a whole range of data from a universe which, despite our leaps in science, remains 96 per cent theoretical.

Fast is likely to broaden our knowledge of everything from pulsars – so far, only 3 per cent of an estimated 60,000 in the galaxy have been found, and the promised discovery of more and weaker types could alter our understanding of how the universe functions – to the contentious concepts of dark matter and dark galaxies.

It could even solve the so-called “small-scale crisis” that is troubling the otherwise widely accepted cosmological model of how our universe evolved and continues to function. This model is based on theories of “cold dark matter” and “dark energy”; problematically, some observations appear to show that on a small scale – in smaller galaxies – the model appears less convincing. One way or the other, Fast could soon resolve the debate.

But it is Fast’s “front page” role that is, predictably, attracting all the headlines – the search for signals from extra-terrestrial life. China claims that Fast, being able to scan up to a million stars, across a broader arc of sky, in a fraction of the time its rivals require to scan only thousands, will outgun all other arrays currently scouring space for signs of intelligent life.

“Searching for extra-terrestrial intelligence is usually considered to be a high-risk task,” states the Chinese National Development and Reform Commission, charged with raising the country’s scientific profile across a range of disciplines and the driving force behind the Fast project. “However, if it succeeds, it will overshadow all other scientific achievements of mankind.”

It is in this endeavour in particular that Fast comes closest to promising the type of knowledge revolution triggered more than 400 years ago by the humble telescope, which swept away so many of our certainties and allowed us to see ourselves, and our universe, in a new and humbling light.

A flurry of improvements followed in the 17th century as other inventors sought to capitalise on Lippershey’s invention – there were obvious practical advantages in the telescope, especially for sailors and soldiers, but it took the Italian astronomer Galileo Galilei to realise that the greatest benefit would come from pointing it at the heavens.

Galileo developed his own telescope, with a magnification of 10, and in 1610 became the first person to study the surface of the Moon. He learnt that its surface was not smooth, as previously had been thought, but “uneven, rough, full of cavities and prominences”, rather like the Earth.

It was the beginning of a scientific, rather than superstitious understanding of the universe, and heralded the dawn of the Age of Enlightenment.

Improving the magnification of his telescope, Galileo went on to study Jupiter, Saturn and Venus. As he discovered more and more about the movements of the planets and the Sun, so he found himself increasingly at odds with the orthodoxy of the Roman Catholic church, which, for theological rather than scientific reasons, held that the Earth was at the centre of the universe.

In 1615, after the Inquisition declared Galileo’s conviction that the Sun was at the centre of our solar system “foolish and absurd in philosophy” he was charged with heresy and spent the last 27 years of his life under house arrest.

Earthbound lens-based telescopes operating in the visual spectrum revolutionised our view of space, but only up to a point. Ultimately, their potential was frustrated by the distorting effects of our atmosphere. At many wavelengths “the Earth’s atmosphere is nearly opaque and glows brightly” says Nasa. For those wavelengths that do make it to the ground, “the Earth’s atmosphere blurs the images and causes stars to twinkle”.

This problem led to the development of telescopes in space, a concept first proposed by US theoretical physicist Lyman Spitzer in 1946. He was ahead of his time, and its technology – the launch of the first satellite was still a decade away. But Spitzer’s vision of a space-based observatory that would not only be unaffected by Earth’s atmospheric distortion but would also span a broad range of wavelengths finally materialised as the Hubble Space Telescope, launched by the Shuttle Discovery in 1990.

Hubble has located 3,000 previously unknown distant galaxies, narrowed the likely age of the universe down to 13.7 billion years, and advanced our knowledge of how and why stars die, galaxies collide and merge and matter is swallowed up by black holes.

Hubble’s successor, the James Webb Space Telescope, a large infrared telescope with a 6.5-metre mirror, is expected to be launched in 2018 and will be equipped with cameras and spectrometers capable of recording extremely faint signals.

Building observatories on Earth, however, is much cheaper than sending them into space, and this is where radio astronomy comes into its own. Their key advantage is that the broad band of radio waves from space they are designed to detect pass through the Earth’s atmosphere unhindered, unlike the X-rays, gamma rays and ultraviolet light at one end of the spectrum, which can only be observed from space, and the long-wavelength radio waves at the other. Even visible light, as seen by the naked eye and basic telescopes, is distorted by our atmosphere.

The first radio waves from space were detected in 1931, purely by accident. Karl G Jansky, a US radio engineer at the Bell telephone company, was tasked with identifying the source of annoying static that was interfering with transatlantic calls.

Using a crude antenna mounted on a turntable fitted with four car wheels, it took him a year to figure out that the source of a faint hiss he kept detecting was not thunderstorms or radiation from the Sun, as he had first thought, but was actually radio waves coming from the Milky Way.

The science of radio astronomy was born and in 2012 the US National Science Foundation’s iconic Very Large Array radio telescope in New Mexico was renamed the Karl G Jansky Very Large Array in his honour.

As much as such instruments teach us about the universe, they also help us to learn about ourselves. Our desire and ability to explore the universe, facilitated by technical developments from Lippershey’s telescope onwards, is as much a philosophical endeavour as it is a purely scientific one, academics have argued.

“Throughout the ages, developments in instrumentation have affected and often stimulated changes in philosophical perspectives related to space,” wrote George Farre, a professor in the philosophy at Georgetown University, Washington, in Nasa’s Space Educator’s Handbook in 1983.

The most fundamental example, he said, was the invention of the telescope: “The discovery of so many new stars with the telescope prompted philosophers to conclude that the naked eye could perceive probably only a small fraction of the universe.” This conclusion, startling at the time, “contributed to the dialogue on the finite or infinite nature of the universe, with the many philosophic implications that debate entailed”.

For Milton K Munitz, a philosophy professor at the City University of New York, the human need to have a “cosmology, an acceptable picture of the universe”, derived from two principal motives. The first was simple curiosity, “a purely intellectual craving and sense of wonder” that seeks answers to such questions as how the universe began, whether it is infinite, what it’s made of and if there is some purpose to its existence.

But the second motive, as he wrote in his 1986 book, Cosmic Understanding – Philosophy and Science of the Universe, stemmed from “the human need to ‘situate’ the life of human beings in the universe”. We wished “to know our ‘place’,” wrote Munitz, “where we fit in among all the other entities that make up the universe.”

Philosophy and science had become inseparable partners in the pursuit of answers to key existential questions: “What forces, powers, and causes brought us into existence and sustain us? What should be our goals, purposes, and values? Is there some cosmic design of which our lives are part?”

In simple terms, concluded Munitz, the pursuit of the secrets of the universe was nothing less than the age-old “search for the meaning of life”.

The telescope didn’t provide the answers. But it was the first technological step down a road that has led to China’s Five-hundred-metre Aperture Spherical Radio Telescope, which could well do so.

Source: art & life

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