Cosmic Quest

Astronomer Heather Couper charts the history of our growing understanding of the universe.

Astronomer Heather Couper on the importance of the sun to ancient agrarian society.

How our ancestors mapped the stories of their mythology onto the constellations in the sky

The history of astrology began as a way of advising rulers on their military campaigns.

Ancient associations of the cosmos with deities, and astrology's link to mathematics.

Greek philosopher Thales thought natural forces cause natural disasters, not acts of gods.

Ptolomy wrote 13 volumes listing over 1000 stars and 48 constellations around AD 150.

Heather Couper considers the Islamic scholar, poet and mathematician, Omar Khayyam.

Copernicus had the crazy idea that the Earth was not at the centre of the universe.

Tycho Brahe realised that the heavens change, and that a planet's orbit could be predicted

Heather Couper on Galileo's idea to systematically record his telescope observations.

Isaac Newton's mathematical brilliance put the laws of physics on a firm foundation.

Heather Couper considers how Edmund Halley went about calculating the orbit of a comet.

Astronomer Heather Couper looks at how Herschel doubled the size of the solar system.

Heather Couper looks at the work of the planet hunter Johann Bode, tracking down asteroids

The science of astrophysics began 300 years ago but rocketed in Victorian times.

The science of astrophysics has emerged over the past 300 years. It began with the first attempts to measure the distances of the stars but took off in late Victorian times with the invention of the spectroscope, a device to split starlight up into its component wavelengths. This led to an understanding of the composition of stars and the discovery of a new element on the Sun.

The science of astrophysics began 300 years ago but rocketed in Victorian times.

Heather considers the struggle to build our knowledge of our own galaxy, the Milky Way.

Galileo realised that the Milky Way was a glowing band of stars across the sky and philosopher Immanuel Kant recognised that our Sun was just one member of a vast star system. But for centuries, few recognised the true nature of our galaxy. In the late 19th century, William Herschel realised that the Milky Way was a giant body of stars, but still his discovery was ignored. It was not until early in the 20th century that Harlow Shapley began to estimate the distances of the stars and hence map out the Milky Way in three-dimensional detail. Radio astronomy finally yielded the ability to penetrate the dark clouds towards the galactic centre and see the true distribution of matter in the skies.

Heather considers the struggle to build our knowledge of our own galaxy, the Milky Way.

Henrietta Swan Leavitt refuted this, studying variable stars and realising that a certain type of star varied at a rate that was linked to its brightness. These so-called Cepheid variables could be used to estimate the vast distances of space.

In 1919, the young Edwin Hubble used a new telescope in California to search for Leavitt's Cepheids in spiral nebulae. He discovered, to his astonishment, that the nearest, the Andromeda nebula, lay well outside our own galaxy and constituted an island universe in its own right.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper traces our understanding of nebulae, island universes outside our galaxy.

In 1845 the third Earl of Rosse completed the biggest telescope in the world at his castle in the centre of Ireland. In spite of cloudy skies, this leviathan enabled him to see spectacular detail in the sky, including a spiral structure in certain fuzzy patches known as nebulae. Some of these seemed so big that astronomers thought they must be rotating clouds of gas out of which planetary systems are born.

Henrietta Swan Leavitt refuted this, studying variable stars and realising that a certain type of star varied at a rate that was linked to its brightness. These so-called Cepheid variables could be used to estimate the vast distances of space.

In 1919, the young Edwin Hubble used a new telescope in California to search for Leavitt's Cepheids in spiral nebulae. He discovered, to his astonishment, that the nearest, the Andromeda nebula, lay well outside our own galaxy and constituted an island universe in its own right.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper traces our understanding of nebulae, island universes outside our galaxy.

A recent twist to this tale came in the year 2000, when estimates of the rate of the expansion revealed that the most distant galaxies are accelerating. The only way to explain this was by a force called dark energy - in effect, a cosmological constant.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

How did the discovery that the universe is expanding impact upon Einstein's theories?

In 1915, Albert Einstein found that he had to introduce a new factor into his equations of gravity to prevent the stars from falling in on one another. He called it the cosmological constant. But then, astronomers discovered that the light from galaxies was stretched in a way that could only be explained if the galaxies were flying apart from each other and the universe was expanding.

A recent twist to this tale came in the year 2000, when estimates of the rate of the expansion revealed that the most distant galaxies are accelerating. The only way to explain this was by a force called dark energy - in effect, a cosmological constant.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

How did the discovery that the universe is expanding impact upon Einstein's theories?

A decisive blow to the latter theory came from a radio telescope in New Jersey in the early 1960s that detected a gentle background glow at microwave radio frequencies that theorists had predicted as the dying embers of the big bang itself.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

The Big Bang theory of how the universe began and what its opponents think.

The discovery that the universe is expanding led cosmologists to suggest that its origin lay in a compact, dense, hot fireball. Cambridge astronomer Fred Hoyle thought this so ridiculous that he disparagingly called it the big bang. The name stuck and there followed intense arguments between supporters of the big bang theory and Fred Hoyle and his colleagues, who favoured a steady state universe.

A decisive blow to the latter theory came from a radio telescope in New Jersey in the early 1960s that detected a gentle background glow at microwave radio frequencies that theorists had predicted as the dying embers of the big bang itself.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

The Big Bang theory of how the universe began and what its opponents think.

In 1967, a field near Cambridge saw a strange new sort of telescope, consisting of 1,000 wooden posts and 120 miles of wire. It was with this that Jocelyn Bell discovered a regular cosmic heartbeat, a regular radio pulse. Researchers initially surmised that it might be a signal from an alien civilisation, but it was later found to emanate from an extremely dense spinning neutron star, the collapsed core of an exploded star or supernova. Soon dozens of these pulsars were known, taking physics to a new level.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

How finding radio waves in space led to the discovery of the pulsar.

Second World War radar research led to the discovery of radio broadcasts from the skies. A new science was born and radio astronomers started to build giant dishes to listen in to the cosmos, including the great radio telescope at Jodrell Bank, brainchild of Bernard Lovell.

In 1967, a field near Cambridge saw a strange new sort of telescope, consisting of 1,000 wooden posts and 120 miles of wire. It was with this that Jocelyn Bell discovered a regular cosmic heartbeat, a regular radio pulse. Researchers initially surmised that it might be a signal from an alien civilisation, but it was later found to emanate from an extremely dense spinning neutron star, the collapsed core of an exploded star or supernova. Soon dozens of these pulsars were known, taking physics to a new level.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

How finding radio waves in space led to the discovery of the pulsar.

A black hole seems to defy notions of common sense and even of normal physics. Light, information and travellers would have no escape from its gravity. At its heart, matter and even space and time would be squashed out of existence. Yet there is a small theoretical chance that someone entering a spinning black hole might survive to emerge in another universe.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper considers how the concept of black holes gained credence in astronomy.

The next breakthrough came from an even more distant object over 2 billion light years away. At its heart was something 40 times more luminous than a normal galaxy yet no bigger than the solar system. These mysterious powerhouses were named quasi-stellar radio sources, now abbreviated to quasars. The consensus now is that they are massive black holes, millions or even billions of times the mass of our Sun, gobbling stars and gas in the centres of galaxies.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper looks at the discovery of quasars - huge black holes a long way from Earth.

The question remains unanswered, though now there are many theories. It is hoped that elaborate experiments in particle accelerators may cast some light on the subject.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper looks at the search for dark matter. What we see is only a fraction of it.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper looks at arguments over the laws of physics and the universe's creation.

Given all that we now know about the formation of stars and planets and the evolution of life on Earth, it might seem as if the mystery is being taken out of the universe. However, every solution seems to throw up a deeper mystery. Within our understanding of physics, there are no known fundamental reasons for much of the astronomical phenomena that we observe. Of course, we can only observe a universe that supports life. This is known as the anthropic principle and has far-reaching implications. Some argue that it makes the universe very special, as if we were meant to be, while others suggest that we inhabit one of the few bio-friendly corners in an almost infinite multiverse of possibilities.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper looks at arguments over the laws of physics and the universe's creation.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper looks at William Herschel's discovery of infrared radiation in 1800.

Infrared radiation was discovered by William Herschel two centuries ago, but only recently has infrared astronomy come of age. Infrared is able to peer inside dark clouds that mask regions of the galaxy such as the Orion Nebula from optical telescopes. Within these clouds we can now see the processes through which the gas clouds contract, heat up and ignite to give birth to a new generation of stars.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper looks at William Herschel's discovery of infrared radiation in 1800.

In the 1950s, Fred Hoyle and his colleagues showed how new elements are created in stars as they burn hydrogen and helium. In the case of relatively small stars such as our sun, the fuel eventually runs out, the bloated outer layers are lost into space and a slowly cooling white dwarf remains. But massive stars begin to collapse in on themselves when fuel runs out at the core, creating a huge explosion known as a supernova.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper looks at research that shows stars are like controlled nuclear explosions.

Until the modern era of astrophysics, nobody knew what made stars shine. The answer arose from the nuclear age. The sun and stars are like giant hydrogen bombs, controlled nuclear explosions.

In the 1950s, Fred Hoyle and his colleagues showed how new elements are created in stars as they burn hydrogen and helium. In the case of relatively small stars such as our sun, the fuel eventually runs out, the bloated outer layers are lost into space and a slowly cooling white dwarf remains. But massive stars begin to collapse in on themselves when fuel runs out at the core, creating a huge explosion known as a supernova.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper looks at research that shows stars are like controlled nuclear explosions.

In 1955 Eugene Shoemaker showed that a crater in Arizona was blasted out by the impact of a large rock from space. He went on to show that most of the craters on the moon resulted from similar impacts, early in the history of the solar system. The dawn of the space age is enabling us to begin to explore the rocks in our cosmic backyard and speculate about worlds beyond.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

How the use of infrared telescopes increased our understanding of distant planets.

For centuries, people have been speculating on the origin of the Earth and other planets. As long ago as 1755 the philosopher Imanuel Kant suggested that our solar system may have been born from a rotating cloud or nebula of gas and dust. But it was not until an infrared telescope was sent into space in 1983 that astronomers began to gather images of such dusty discs around other young stars.

In 1955 Eugene Shoemaker showed that a crater in Arizona was blasted out by the impact of a large rock from space. He went on to show that most of the craters on the moon resulted from similar impacts, early in the history of the solar system. The dawn of the space age is enabling us to begin to explore the rocks in our cosmic backyard and speculate about worlds beyond.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

How the use of infrared telescopes increased our understanding of distant planets.

Even today, with the best telescopes in the world, it remains impossible to see planets around distant stars. But in the last decade, astronomers have gathered indirect evidence for many other planetary systems. The easiest to detect and hence the first to be found were the most amazing - planets bigger than Jupiter orbiting so close to their star that they are almost touching. But evidence is now emerging that solar systems more like our own exist, some with multiple planets and some with planets that may be like Earth.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

The work by contemporary astronomers to find other planets like Earth in the universe.

In the 16th century, Giordano Bruno speculated that there must be other planets similar to our own in the universe. He was burned at the stake for this and other heresies.

Even today, with the best telescopes in the world, it remains impossible to see planets around distant stars. But in the last decade, astronomers have gathered indirect evidence for many other planetary systems. The easiest to detect and hence the first to be found were the most amazing - planets bigger than Jupiter orbiting so close to their star that they are almost touching. But evidence is now emerging that solar systems more like our own exist, some with multiple planets and some with planets that may be like Earth.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

The work by contemporary astronomers to find other planets like Earth in the universe.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper considers the prospects of life being found elsewhere in the solar system.

She looks at the prospects for life elsewhere in our own solar system. Could evidence of life have even been discovered already on Mars? She tells the story of the search for extra-terrestrial intelligence as scientists scan the skies for messages from the stars.

Readers are Timothy West, Robin Sebastian, Julian Rhind-Tutt and John Palmer.

Heather Couper considers the prospects of life being found elsewhere in the solar system.