Science: Witness to the early universe

The Hubble Space Telescope is to be superseded by something even more powerful.

WHEN GALILEO directed his small telescope towards the sky in 1610, his observations changed our view of the universe for ever. Today anyone with good binoculars can see what Galileo saw: Venus displays phases just like the Moon, and the stars remain like points of light rather than the discs of the planets. The stars, to appear as points, had to be much farther away than the planets, showing that the universe was a far bigger place than anybody had believed before. Galileo showed that the Earth was not the centre of the universe, but rotates around the Sun.

Since Galileo, astronomy has leapt forward whenever a new and more powerful telescope has become available. One of the best examples was when the Hubble Space Telescope (HST) launched in April 1990. Astronomers obtained images showing that areas in the sky that had previously looked blank are in fact filled with thousands of distant, very faint galaxies.

Although astronomers plan to use the HST until the year 2010, the American National Aeronautics and Space Administration (Nasa), and the European Space Agency (ESA) are already planning Hubble's successor, the Next Generation Space Telescope (NGST). Since it will be much more powerful, astronomers expect the instrument to open up a new window of discovery. "It will see the first significant burst of star formation in the universe," says Gerry Gilmore, an astronomer at Cambridge University who has vast experience of using the HST.

The present plant is to launch the NGST in 2007. Europe has committed itself to contributing $200m towards the total price of about $1bn. Although ESA's science programme is short of funds, its readiness to participate is largely based on the extremely good experience over the collaboration with the HST, whereby European astronomers are obtaining more than 20 per cent of total available observation time.

The HST still looks like a conventional telescope - a tube with an opening at one end and a parabolic mirror at the other end - but the design of the NGST will be radically different. It can dispense with the tube, because it will be placed in a point in space much darker than the relatively low orbit of the HST.

It will circle the Sun in an orbit about a million miles wider than that of the Earth, but it will do this at the same speed as the Earth. The gravitational pulls of the Sun and Earth conspire to create a stable spot about a million miles away on the Sun-Earth axis, which will an be exploited by the new telescope. The main mirror will also be much larger than that of the HST: current plans call for a diameter of 8 metres - so will be able to gather about 10 times more light than the HST.

The NGST will observe distant celestial objects in visible light, but also infrared light. The human eye cannot detect infrared light, but we can feel it as the warmth of the Sun. Optical mirrors can focus infrared light just as well as visible light. However, the colder a telescope is, the higher the sensitivity of its detectors for infrared light, and therefore the NGST will be equipped with a heat shield to protect it from the Sun's radiation. This will cool it to a temperature of -243C (just 30C above absolute zero).

Infrared light is useful for observing dark objects, such as dust and protoplanetary rings around stars, because of their heat radiation. "Most of these things are typically at room temperature, and most of the energy is coming out at the near infrared, which is exactly where NGST will work well,'' says Gilmore.

However, astronomers will also need to use infrared light if they want to observe galaxies born shortly after the Big Bang about 12 billion years ago, when the universe began. Since the universe is still expanding, these galaxies are extremely distant and are moving away from the Earth at tremendous speeds.

Just as the pitch of a train's horn moving away from us at high speed is lowered - a phenomenon know as the Doppler effect - the wavelength of visible light from distant galaxies becomes extended, and so moves into the infrared. Astronomers call this effect "redshift".'

The NGST "will see directly the first generation of stars forming; it will see the blue light coming out from them that will be redshifted into the near infrared,'' says Gilmore. The infrared capabilities of the HST are much more limited.

Because the shift in wavelength is an indicator of velocity, the NGST will be also be able to study the rotation of stars and gases around the nuclei of galaxies. Because these stars move fast, the galaxies are suspected to contain massive, invisible black holes at their centres. The NGST "will probably be best at all at mapping black holes in normal galaxies,'' says Gilmore. "It will be able to tell us how many black holes there are.''

The challenges of placing an 8- metre mirror in space will be daunting. Although the optics are simple and will not require `'adaptive'' technology - there is no gravity to deform the mirror and no atmosphere to distort arriving light - the mirror will have to be sturdy yet lightweight. The designers are therefore planning to make the mirror out of beryllium.

Current plans give this mirror a central, 4-metre section and two folding sections to extend the central mirror to a diameter of 8 metres. It is in this respect that European industry will play an important role: "It is quite clear that in some areas, particularly in light-weight mirror technology and polishing, Europe is really playing a leading role,'' says Piero Benvenuti, an NGST project scientist at the European Space Agency. Benvenuti says that Nasa is already rewarding subcontracts for polishing test mirrors to a French company that has been contracted to build the four 8.2-metre mirrors of the largest telescope on Earth, now under construction in Chile by the European Southern Observatory (ESO). "Europe has the technological potential to participate at a very high level,'' says Benvenuti. And Peter Stockman, an NGST project scientist at the Space Telescope Science Institute in Baltimore, from where the NGST will be controlled, thinks it is possible that Europe may supply all the optics for the NGST: "European optics manufacturing is superb,'' he says.

Roger Davies, professor of astronomy at Durham University, who is a leading supporter of the next generation telescope, says the project has far-reaching implications for the study of the cosmos. `'We expect to see the birth of stars and galaxies. We will witness the act of creating the very stuff we are made of. This telescope will see back in time to when the universe was just a tenth of the age it is today.''

The NGST - "son of Hubble" - the most advanced telescope ever built, will be a sophisticated time machine for looking back at the violent birth of the universe.

PROMOTED VIDEO
Arts and Entertainment
Gothic revival: artist Dave McKean’s poster for Terror and Wonder: The Gothic Imagination
Exhibition
Arts and Entertainment
Diana Beard has left the Great British Bake Off 2014

TV
Have you tried new the Independent Digital Edition apps?
Arts and Entertainment
Lisa Kudrow, Courtney Cox and Jennifer Anniston reunite for a mini Friends sketch on Jimmy Kimmel Live

TV
Arts and Entertainment
TVDessert week was full of the usual dramas as 'bingate' ensued
Arts and Entertainment
Clara and the twelfth Doctor embark on their first adventure together
TVThe regulator received six complaints on Saturday night
Arts and Entertainment
Vinyl demand: a factory making the old-style discs
musicManufacturers are struggling to keep up with the resurgence in vinyl
Arts and Entertainment
David Baddiel concedes his show takes its inspiration from the hit US series 'Modern Family'
comedyNew comedy festival out to show that there’s more to Jewish humour than rabbi jokes
Arts and Entertainment
Puff Daddy: One Direction may actually be able to use the outrage to boost their credibility

music
Arts and Entertainment
Suha Arraf’s film ‘Villa Touma’ (left) is set in Ramallah and all the actresses are Palestinian

film
Arts and Entertainment
Madame Vastra and Jenny Flint kiss in Doctor Who episode 'Deep Breath'

TV
Arts and Entertainment
Steve Carell in the poster for new film 'Foxcatcher'
filmExclusive: First look at comic actor in first major serious role
Arts and Entertainment

TV
Arts and Entertainment
Kingston Road in Stockton is being filmed for the second series of Benefits Street
arts + entsFilming for Channel 4 has begun despite local complaints
Arts and Entertainment
Led Zeppelin

music
Arts and Entertainment
Radio presenter Scott Mills will be hitting the Strictly Come Dancing ballroom
TV
Arts and Entertainment

TV
Arts and Entertainment

TV
Arts and Entertainment
The Doctor and Clara have their first real heart to heart since he regenerated in 'Deep Breath'
tv
Arts and Entertainment
Beyonce performs in front of a Feminist sign at the MTV VMAs 2014

music
Arts and Entertainment
Miley Cyrus has taken home the prize for Video of the Year at the MTV Video Music Awards 2014

music
Arts and Entertainment
Peter Paige and Scott Lowell in Queer as Folk (Season 5)
tvA batch of shows that 'wouldn't get past a US network' could give tofu sales an unexpected lift
Arts and Entertainment
books... but seller will be hoping for more
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    Ukraine crisis: The phoney war is over as Russian troops and armour pour across the border

    The phoney war is over

    Russian troops and armour pour into Ukraine
    Potatoes could be off the menu as crop pests threaten UK

    Potatoes could be off the menu as crop pests threaten UK

    The world’s entire food system is under attack - and Britain is most at risk, according to a new study
    Gangnam smile: why the Chinese are flocking to South Korea to buy a new face

    Gangnam smile: why the Chinese are flocking to South Korea to buy a new face

    Seoul's plastic surgery industry is booming thanks to the popularity of the K-Pop look
    From Mozart to Orson Welles: Creative geniuses who peaked too soon

    Creative geniuses who peaked too soon

    After the death of Sandy Wilson, 90, who wrote his only hit musical in his twenties, John Walsh wonders what it's like to peak too soon and go on to live a life more ordinary
    Caught in the crossfire of a cyber Cold War

    Caught in the crossfire of a cyber Cold War

    Fears are mounting that Vladimir Putin has instructed hackers to target banks like JP Morgan
    Salomé's feminine wiles have inspired writers, painters and musicians for 2,000 years

    Salomé: A head for seduction

    Salomé's feminine wiles have inspired writers, painters and musicians for 2,000 years. Now audiences can meet the Biblical femme fatale in two new stage and screen projects
    From Bram Stoker to Stanley Kubrick, the British Library's latest exhibition celebrates all things Gothic

    British Library celebrates all things Gothic

    Forthcoming exhibition Terror and Wonder: The Gothic Imagination will be the UK's largest ever celebration of Gothic literature
    The Hard Rock Café's owners are embroiled in a bitter legal dispute - but is the restaurant chain worth fighting for?

    Is the Hard Rock Café worth fighting for?

    The restaurant chain's owners are currently embroiled in a bitter legal dispute
    Caribbean cuisine is becoming increasingly popular in the UK ... and there's more to it than jerk chicken at carnival

    In search of Caribbean soul food

    Caribbean cuisine is becoming increasingly popular in the UK ... and there's more to it than jerk chicken at carnival
    11 best face powders

    11 best face powders

    Sweep away shiny skin with our pick of the best pressed and loose powder bases
    England vs Norway: Roy Hodgson's hands tied by exploding top flight

    Roy Hodgson's hands tied by exploding top flight

    Lack of Englishmen at leading Premier League clubs leaves manager hamstrung
    Angel Di Maria and Cristiano Ronaldo: A tale of two Manchester United No 7s

    Di Maria and Ronaldo: A tale of two Manchester United No 7s

    They both inherited the iconic shirt at Old Trafford, but the £59.7m new boy is joining a club in a very different state
    Israel-Gaza conflict: No victory for Israel despite weeks of death and devastation

    Robert Fisk: No victory for Israel despite weeks of devastation

    Palestinians have won: they are still in Gaza, and Hamas is still there
    Mary Beard writes character reference for Twitter troll who called her a 'slut'

    Unlikely friends: Mary Beard and the troll who called her a ‘filthy old slut’

    The Cambridge University classicist even wrote the student a character reference
    America’s new apartheid: Prosperous white districts are choosing to break away from black cities and go it alone

    America’s new apartheid

    Prosperous white districts are choosing to break away from black cities and go it alone