RSSArchive for January, 2013

Telescope takes universe’s temperature

Australia Telescope Compact Array

CSIRO’s Australia Telescope Compact Array, used the make the temperature measurements.

ASTRONOMERS USING a CSIRO radio telescope have taken the universe’s temperature, and have found that it has cooled down just the way the Big Bang theory predicts.

Using the Australia Telescope Compact Array near Narrabri, NSW, an international team from Sweden, France, Germany and Australia has measured how warm the universe was when it was half its current age.

“This is the most precise measurement ever made of how the universe has cooled down during its 13.77 billion year history,” said Dr Robert Braun, Chief Scientist at CSIRO Astronomy and Space Science.

Because light takes time to travel, when we look out into space we see the universe as it was in the past – as it was when light left the galaxies we are looking at. So to look back halfway into the universe’s history, we need to look halfway across the universe.

Cosmic fingerprint

How can we measure a temperature at such a great distance?

Illustration of radio waves coming from a distant quasar through a galaxy in the foreground and then on to Earth.

Radio waves from a distant quasar pass through another galaxy on their way to Earth. Changes in the radio waves indicate the temperature of the gas in that galaxy.

The astronomers studied gas in an unnamed galaxy 7.2 billion light-years away (at a redshift of 0.89).

The only thing keeping this gas warm is the cosmic background radiation – the glow left over from the Big Bang.

By chance, there is another powerful galaxy, a quasar (called PKS 1830-211), lying behind the unnamed galaxy.

Radio waves from this quasar come through the gas of the foreground galaxy. As they do so, the gas molecules absorb some of the energy of the radio waves. This leaves a distinctive ‘fingerprint’ on the radio waves.

From this ‘fingerprint’ the astronomers calculated the gas’s temperature. They found it to be 5.08 Kelvin (-267.92 degrees Celsius): extremely cold, but still warmer than today’s universe, which is at 2.73 Kelvin (-270.27 degrees Celsius).

Exactly as predicted

According to the Big Bang theory, the temperature of the cosmic background radiation drops smoothly as the universe expands.

“That’s just what we see in our measurements,” said research team leader Dr. Sebastien Muller of Onsala Space Observatory at Chalmers University of Technology in Sweden. “The universe of a few billion years ago was a few degrees warmer than it is now, exactly as the Big Bang theory predicts.”

Adapted from information issued by CSIRO. Images David Smyth and Onsala Space Observatory.

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From darkness comes the light

Lupus 3 dark cloud

The Lupus 3 dark cloud, about 600 light-years from Earth, is a region where new stars are forming. Alongside is a cluster of brilliant stars that have already emerged from their dusty stellar nursery.

  • Lupus 3 stellar nursery is about 600 light-years from Earth
  • New stars are forming out of the dark dust clouds

A NEW IMAGE RELEASED by the European Southern Observatory shows a dark cloud where new stars are forming, along with a cluster of brilliant stars that have already emerged from their dusty stellar nursery.

The new picture was taken with the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile and is the best image ever taken at visible light wavelengths of this little-known object.

The cloud is known as Lupus 3, and it lies about 600 light-years from Earth. The section shown here is about five light-years across.

On the left of this new image there is a dark cloud that contains huge amounts of cool cosmic dust and is a nursery where new stars are being born. It is likely that the Sun formed in a similar star formation region more than four billion years ago.

As the denser parts of such clouds contract under the effects of gravity they heat up and start to shine – they’re new stars. At first their light is blocked by the dusty clouds and can be seen only by telescopes observing at longer wavelengths than visible light, such as infrared. But as the stars get hotter and brighter, their intense radiation and stellar winds gradually clear the clouds around them until they emerge in all their glory.

The bright stars on the right are a perfect example. Some of their brilliant blue light is being scattered off the remaining dust around them. The two brightest stars can be seen easily with a small telescope or binoculars. They are young stars that have not yet started to shine by nuclear fusion in their cores and are still surrounded by glowing gas. They’re probably less than one million years old.

Wider view of Lupus 3

A wider view of Lupus 3 shows the extent of the dark dust cloud, silhouetted against the starry background of our galaxy.

Adapted from information issued by ESO. Images courtesy ESO / F. Comeron / Digitised Sky Survey 2 / Davide De Martin.

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Remembering Apollo 5

PRIOR TO THE SUCCESSFUL manned lunar landings of the 1960s-’70s, NASA conducted a series of test flights, both crewed and uncrewed. One of those was the uncrewed Apollo 5 flight, which saw the first test (in Earth orbit) of the lunar module.

Apollo 5 (LM-1/Saturn 204) was launched from the Kennedy Space Centre’s Launch Complex 37 on January 22, 1968. The Lunar Module-1 payload was boosted into Earth orbit by a launch vehicle composed of a Saturn IB first stage and a Saturn S-IVB second stage. The Apollo lunar module’s first flight test was called a complete success. Ascent and descent propulsion systems and the ability to abort a lunar landing and return to orbit were demonstrated.

Adapted from information issued by NASA.

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No giant leap for mankind

Digital clock graphic showing a leap second

Notice anything strange? On a normal day, the clock would go from 23:59:59 to 00:00:00. But when we have a leap second, there is an extra second added, which would make the display read “60”, before going on to 00:00:00. It has been calculated that a leap second will not be needed in June 2013.

 

THE WORLD BODY that regulates our planet’s timekeeping system, has announced that there will not be a leap second added at the end of June this year.

Leap seconds are added from time to time (no pun intended) in order to keep two different time systems in sync – the time measured by the spin of the Earth, and that kept by atomic clocks.

The time measured by the Earth’s spin is the one that has been used for thousands of years. One rotation of the Earth – a day – is broken down into 24 hours, with each hour having 60 minutes and each minute having 60 seconds. That means there are 86,400 seconds in one day.

Or, to put it another way, the length of a second is 1/86,400th of one day. So what we call one second, is entirely dependent on being that fraction of the length of one rotation of the Earth.

The problem is, the Earth makes for a pretty rotten clock. Its rate of rotation is not constant – it speeds up and slows down over the course of a year, and from year to year is gradually slowing down. The overall rate of slowing is about 0.002 of a second per day, per century. That means if you measured the length of the day today, and then came back in 100 years, a day in the future would be 0.002 of a second shorter.

It doesn’t sound like much, and for centuries this was just fine. Hardly anyone needed to make measurements of time with a precision greater than one second. And those who did, limited themselves to perhaps tenths or hundredths of second, easily achievable with precision timepieces.

Here’s a fun little video that shows how scientists can tell the Earth is a poor clock:

But by the middle of the 20th century, the requirements for measuring time had become far more stringent. Our technology – computers and communications – plus sciences such as astronomy and physics, demanded better precision and regularity.

And so atomic clocks were invented. Atomic clocks keep extraordinarily precise and regular time. Since the late 1960s, our time system has been based on these atomic clocks, which are located in scientific institutions in many parts of the world.

The problem is, with atomic clocks keeping precise, regular time, but with the Earth gradually slowing down, the “natural” time of the day according to Earth’s rotation gets out of sync with atomic time. Earth falls behind. So every now and then, the powers-that-be decree that a one second delay needs to put into the atomic clock system to let the Earth catch up. And that’s what a leap second is.

It’s a bit like a parade of troops being ordered to march on the spot for a moment, to let the stragglers catch up.

Leap seconds can be added (or subtracted) at the end of June and December each year. But they’re not always necessary, and some years there aren’t any leap seconds at all. Since 1972, they’ve been added in June only 10 times; in December, 15 times. (On only one of those occasions, 1972, was a leap second added in both June and December).

Incidentally, most developed countries have their own institutes for maintaining standards in measurement, be it length, mass, electrical properties, time, and so on. In a nod to Dr Who, the person responsible for time at each institute is known as that country’s Time Lord. You can listen to (or read the transcript of) an interview I did a few years ago with Australia’s Time Lord, Dr Bruce Warrington, here: The Science Show

More information:

Wikipedia entry on leap seconds

Story by Jonathan Nally. Digital clock graphic courtesy Wikimedia Commons.

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The Manatee Nebula

W50 supernova remnant

The W50 supernova remnant – now known as the Manatee Nebula – seen at radio wavelengths (green) against the background of stars and dust (seen at infrared wavelengths).

  • Supernova remnant cloud imaged by VLA radio telescope system
  • The cloud closely resembles the endangered Florida manatee
  • Manatees are gentle giants, until black holes, which are far from gentle

A NEW VIEW of a 20,000-year-old supernova remnant and shows how this giant cloud resembles a beloved endangered species, the Florida Manatee.

Known as W50, the supernova remnants is one of the largest ever viewed by the US National Science Foundation’s (NSF) Karl G. Jansky Very Large Array (VLA), which has recently been upgraded. Nearly 700 light-years across, seen from Earth W50 covers two degrees on the sky – that’s as wide as four full Moons.

The enormous W50 cloud formed when a giant star, 18,000 light-years away, exploded as a supernova around twenty thousand years ago, sending its outer gases flying outward in an expanding bubble.

The remaining, gravitationally-crushed relic of that giant star, most likely a black hole, feeds on gas from a very close, companion star. The cannibalised gas collects in a swirling cloud around the black hole.

The black hole’s powerful magnetic field snags charged particles out of the cloud and channels them outward in powerful jets travelling at nearly the speed of light.

The system shines brightly in both radio waves and X-rays and is known collectively as the SS 433 microquasar.

Over time, the microquasar’s jets have forced their way through the expanding gases of the W50 bubble, eventually punching bulges outward on either side. The jets also wobble, like an unstable spinning top, and blaze vivid corkscrew patterns across the inflating bulges.

Florida manatee

A Florida manatee rests underwater in Three Sisters Springs in Crystal River, Florida.

New namesake

When the W50 image reached the NRAO director’s office, Heidi Winter, the director’s executive assistant, saw the likeness to a manatee, the endangered marine mammals known as ‘sea cows’ that congregate in warm waters in the south-eastern United States.

Florida manatees are gentle giants that average around three metres long, weigh over 500kg, and spend up to eight hours a day grazing on sea plants. They occupy the remainder of their day resting, often on their backs with their flippers crossed over their large bellies, in a pose closely resembling W50.

Dangerous encounters with boat propellers injure many of these curious herbivores, giving them deep, curved scars similar in appearance to the arcs made by the powerful jets on the large W50 remnant.

Thanks to Ms Winter’s suggestion, the National Radio Astronomy Observatory has adopted a new nickname for W50: The Manatee Nebula.

Adapted from information issued by NRAO. W50 image courtesy NRAO / AUI / NSF, K. Golap, M. Goss; NASA’s Wide Field Survey Explorer (WISE). Manatee image courtesy Tracy Colson.

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Europe/NASA join forces for next step

Artist's concept of the joint Orion/ATV module in Earth orbit

An artist’s impression of the cone-shaped NASA Orion craft attached to the cylindrical European ATV-based service module in Earth orbit. The service module will supply power generated by four solar panel ‘wings’.

  • Europe’s service module to power/supply NASA’s crew module
  • Similar in concept to Apollo’s service and command modules
  • First test flight, a lunar fly-by, set for 2017

NASA’S ORION SPACECRAFT will carry astronauts further into space than ever before using a module based on Europe’s Automated Transfer Vehicles (ATV).

ATV’s distinctive four-wing solar array is recognisable in this concept. The ATV-derived service module, sitting directly below Orion’s crew capsule, will provide propulsion, power, thermal control, as well as supplying water and gas to the astronauts in the habitable module.

The first Orion mission will be an uncrewed lunar fly-by in 2017, returning for a re-entry into Earth’s atmosphere at a speed of 11 kilometres per second – the fastest re-entry ever.

Artist's impression of an Orion/ATV-based craft approaching an asteroid

In this artist’s impression, an Orion crew module and ATV-based service module are attached to further modules and a solar power array as they approach an asteroid. The supplies carried by, and energy generated by, the service module, will enable medium-duration missions to be attempted.

Albert Einstein to launch

This collaboration between ESA and NASA continues the spirit of international cooperation that forms the foundation of the International Space Station.

Automated Transfer Vehicles (ATVs) have been resupplying the International Space Station since 2008. The fourth in the series, named Albert Einstein, is being readied for launch this year from Europe’s spaceport in Kourou, French Guiana.

The ATV-derived service module, sitting directly below Orion’s crew capsule, will provide propulsion, power, thermal control, as well as supplying water and gas to the astronauts in the habitable module.

Artist's concept of the joint Orion/ATV module

The ATV-based service module will carry the craft’s main propulsion rocket, the nozzle of which can be seen on the right of this artist’s impression.

Critical element for exploration

The ATV performs many functions during missions to the International Space Station. The space freighter reboosts the Station into higher altitudes and can even push the orbital complex out of the way of space debris. While docked, ATV becomes an extra module for the astronauts. Lastly, at the end of its mission it leaves the Space Station with waste materials.

“ATV has proven itself on three flawless missions to the Space Station and this agreement is further confirmation that Europe is building advanced, dependable spacecraft,” said Nico Dettmann, Head of ATV’s production programme.

Thomas Reiter, ESA director of Human Spaceflight and Operations says: “NASA’s decision to co-operate with ESA on their exploration programme with ESA delivering a critical element for the mission is a strong sign of trust and confidence in ESA’s capabilities, for ESA it is an important contribution to human exploration.”

Adapted from information issued by NASA / ESA.

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Space Station to test inflatable module

NASA HAS ANNOUNCED PLANS for an addition to the International Space Station… one that will use the orbiting laboratory to test expandable space habitat technology.

NASA has awarded a US$17.8 million contract to Bigelow Aerospace to provide a Bigelow Expandable Activity Module (BEAM), which is scheduled to arrive at the space station in 2015 for a two-year technology demonstration.

The BEAM is scheduled to launch aboard the eighth SpaceX cargo resupply mission to the station contracted by NASA, currently planned for 2015.

Following the arrival of the SpaceX Dragon spacecraft carrying the BEAM to the station, astronauts will use the station’s robotic arm to install the module on the aft port of the Tranquility node.

After the module is berthed to the Tranquility node, the station crew will activate a pressurisation system to expand the structure to its full size using air stored within the packed module.

Garver and Bigelow next to the Bigelow BEAM

NASA Deputy Administrator Lori Garver and President and founder of Bigelow Aerospace Robert T. Bigelow, talk while standing next to the Bigelow Expandable Activity Module (BEAM) during a media briefing.

A unique test bed

During the two-year test period, station crewmembers and ground-based engineers will gather performance data on the module, including its structural integrity and leak rate.

An assortment of instruments embedded within module also will provide important insights on its response to the space environment. This includes radiation and temperature changes compared with traditional aluminium modules.

“The International Space Station is a uniquely suited test bed to demonstrate innovative exploration technologies like the BEAM,” said William Gerstenmaier, associate administrator for human exploration and operations at NASA Headquarters in Washington.

“As we venture deeper into space on the path to Mars, habitats that allow for long-duration stays in space will be a critical capability. Using the station’s resources, we’ll learn how humans can work effectively with this technology in space, as we continue to advance our understanding in all aspects for long-duration spaceflight aboard the orbiting laboratory.”

Astronauts periodically will enter the module to gather performance data and perform inspections. Following the test period, the module will be jettisoned from the station, burning up on re-entry.

Adapted from information issued by NASA.

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Hubble spots a hidden treasure

Josh Lake's image of LHA 120-N11

Josh Lake’s image of LHA 120-N11, which comprises several adjacent pockets of gas and star formation. It is located in the Large Magellanic Cloud galaxy, roughly 200,000 light-years from Earth.

NEARLY 200,000 LIGHT-YEARS from Earth, the Large Magellanic Cloud, a satellite galaxy of the Milky Way, floats in space, in a long and slow dance around our galaxy.

Vast clouds of gas within it slowly collapse to form new stars. In turn, these light up the gas clouds in a riot of colours, visible in this image from the NASA/ESA Hubble Space Telescope.

The Large Magellanic Cloud (LMC) is ablaze with star-forming regions. From the Tarantula Nebula, the brightest stellar nursery in our cosmic neighbourhood, to LHA 120-N 11, part of which is featured in this Hubble image, the small and irregular galaxy is scattered with glowing nebulae, the most noticeable sign that new stars are being born.

The LMC is in an ideal position for astronomers to study the phenomena surrounding star formation. It lies in a fortuitous location in the sky, far enough from the plane of the Milky Way that it is neither outshone by too many nearby stars, nor obscured by the dust in the Milky Way’s centre.

It is also close enough to study in detail (less than a tenth of the distance of the Andromeda Galaxy, the closest spiral galaxy), and lies almost face-on to us, giving us a bird’s eye view.

Smokey remains of dead stars

LHA 120-N 11 (known as N11 for short) is a particularly bright region of the LMC, consisting of several adjacent pockets of gas and star formation. NGC 1769 (in the centre of this image) and NGC 1763 (to the right) are among the brightest parts.

In the centre of this image, a dark finger of dust blots out much of the light. While nebulae are mostly made of hydrogen, the simplest and most plentiful element in the universe, dust clouds are home to heavier and more complex elements, which go on to form rocky planets like the Earth.

Much finer than household dust (it is more like smoke), this interstellar dust consists of material expelled from previous generations of stars as they died.

The data in this image were identified by Josh Lake, an astronomy teacher at Pomfret School in Connecticut, USA, in the Hubble’s Hidden Treasures image processing competition. The competition invited members of the public to dig out unreleased scientific data from Hubble’s vast archive, and to process them into stunning images.

Josh Lake won first prize in the competition with an image (below) contrasting the light from glowing hydrogen and nitrogen in N 11. The image at the top of the page combines the data he identified with additional exposures taken in blue, green and near infrared light.

Josh Lake's image of NGC 1763

Josh Lake’s image of the NGC 1763 region of nebulosity and stars in the Large Magellanic Cloud galaxy. The image won him first prize in Hubble’s Hidden Treasures Image Processing Competition

More information: Hidden Treasures

Adapted from information issued by ESA / Hubble Information Centre. Images: NASA, ESA and J. Lake.

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Black holes grow faster than expected

Artist's impression of a black hole about to devour a star

Artist’s impression of a black hole about to devour a star. Supermassive black holes are thought to be at the heart of all major galaxies. Australian researchers have determined that as a galaxy grows, its black hole grows even faster.

  • Supermassive black holes have up to billions of times more mass than the Sun
  • How they became this big has been a long-standing mystery
  • Australia research shows big galaxies breed even bigger black holes

ASTRONOMERS FROM SWINBURNE UNIVERSITY of Technology in Australia have discovered how supermassive black holes grow – and it’s not what was expected.

For years, scientists had believed that supermassive black holes – millions or billions of times the mass of our Sun – located at the centres of galaxies, increased their mass in step with the growth of their host galaxy.  However, new observations have revealed a dramatically different behaviour.

“Black holes have been growing much faster than we thought,” Professor Alister Graham from Swinburne’s Centre for Astrophysics and Supercomputing said.

Within galaxies, there is a competition of sorts for the available gas; for either the formation of new stars or feeding the central black hole.

For more than a decade the leading models and theories have assigned a fixed fraction of the gas to each process, effectively preserving the ratio of black hole mass to galaxy mass. New research to be published in The Astrophysical Journal reveals that this approach needs to be changed.

“We now know that each ten-fold increase of a galaxy’s stellar mass is associated with a much larger 100-fold increase in its black hole mass,” Professor Graham said. “This has widespread implications for our understanding of galaxy and black hole co-evolution.”

The following animation depicts a star being devoured by a black hole.

Unexpected behaviour

The researchers have also found the opposite behaviour to exist among the tightly packed clusters of stars that are observed at the centres of smaller galaxies and in disc galaxies like our Milky Way.

“The smaller the galaxy, the greater the fraction of stars in these dense, compact clusters,” Swinburne researcher Dr Nicholas Scott said. “In the lower mass galaxies the star clusters, which can contain up to millions of stars, really dominate over the black holes.”

Previously it was thought that the star clusters contained a constant 0.2 per cent of the galaxy mass.

Black holes = gravitational prisons

The research also appears to have solved a long-standing mystery in astronomy. ‘Intermediate mass’ black holes with masses between that of a single star and one million stars have been remarkably elusive.

The new research predicts that numerous galaxies already known to harbour a black hole – albeit of a currently unknown mass – should contain these missing `intermediate mass’ black holes.

Artist's impression of a black hole in a star field

Intermediate or middle-sized black holes have proved elusive (artist’s impression).

“These may be big enough to be seen by the new generation of extremely large telescopes,” Dr Scott said.

Professor Graham said these black holes were still capable of readily devouring any stars and their potential planets if they ventured too close.

“Black holes are effectively gravitational prisons and compactors, and this may have been the fate of many past solar systems,” Professor Graham said. “Indeed, such a cosmic dance will contribute at some level to the transformation of nuclear star clusters into massive black holes.”

The researchers combined observations from the Hubble Space Telescope, the European Very Large Telescope in Chile and the Keck Telescope in Hawaii to create the largest sample to date of galaxies with reliable star cluster and supermassive black hole mass measurements.

Adapted from information issued by Swinburne University of Technology. Images by Gabriel Perez Diaz.

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Earth-sized planets common in the Milky Way

Artist's impression of an Earth-like exoplanet

There are billions of Sun-like stars in our galaxy, 17 percent of which have close-orbiting planets not much bigger than Earth. Image: ESO/M. Kornmesser.

  • NASA’s Kepler space mission aims to detect Earth-like planets
  • New analysis shows that early Kepler analyses missed over 30 planets
  • It’s now thought 17% of Sun-like stars have planets not much bigger than Earth

AN ANALYSIS OF THE FIRST three years of data from NASA’s Kepler mission, which already has detected thousands of potential exoplanets, contains good news for those searching for habitable worlds outside our Solar System.

It shows that 17 percent of all Sun-like stars have planets one to two times the diameter of Earth orbiting close to their host stars, according to a team of astronomers from the University of California, Berkeley, and the University of Hawaii at Manoa.

This estimate includes only planets that circle their stars within a distance of about one-quarter of Earth’s orbital radius – which would be well within the orbit of Mercury if it were in our Solar System. This is the current limit of Kepler’s detection capability.

Further evidence suggests that the fraction of stars having planets the size of Earth or slightly bigger orbiting within Earth-like orbits may amount to 50 percent.

The team – UC Berkeley graduate student Erik Petigura, former UC Berkeley post-doctoral fellow Andrew Howard, now on the faculty of the Institute for Astronomy at the University of Hawaii, and UC Berkeley professor of astronomy Geoff Marcy – reported its findings on Wednesday (Australian time) at a session on the Kepler mission during the American Astronomical Society meeting in Long Beach, California.

Not necessarily habitable

Planets one to two times the size of Earth are not necessarily habitable. Painstaking observations by Petigura’s team show that planets two or three times the diameter of Earth are typically like Uranus and Neptune, which have a rocky core surrounded by helium and hydrogen gases and perhaps water. Planets close to a star may even be water worlds – planets with oceans hundreds of kilometres deep above a rocky core.

Nevertheless, planets between one and two times the diameter of Earth may well be rocky and, if located within the Goldilocks orbital zone – not too hot, not too cold, just right for liquid water – could support life.

“Kepler’s one goal is to answer a question that people have been asking since the days of Aristotle: What fraction of stars like the Sun have an Earth-like planet?” said Howard. “We’re not there yet, but Kepler has found enough planets that we can make statistical estimates.”

Plot of Kepler and TERRA exoplanets

Using a computer program called TERRA, scientists have sifted extra exoplanets (red dots) out of the existing Kepler data (grey dots). Image by Erik Petigura and Geoff Marcy, UC Berkeley, and Andrew Howard, Institute for Astronomy, University of Hawaii.

Finding planets in the ‘noise’

The estimates are based on a better understanding of the percentage of big Earth-size planets that Kepler misses because of uncertainties in detection, which the team estimates to be about one in four, or 25 percent.

To find planets, the Kepler telescope captures repeated images of 150,000 stars in a region of the sky in the constellation Cygnus. The data are analysed by computer software – the “pipeline” – in search of stars that dim briefly as a result of a planet passing in front, called a transit.

For planets as large as Jupiter, the star may dim by 1 percent, or one part in 100, which is easily detectable. A planet as small as Earth, however, dims the star by one part in 10,000, which is likely to be lost in the data ‘noise’, Petigura said.

The missing worlds

So Petigura spent the past two years writing a software program called TERRA, which is very similar to Kepler’s pipeline. The team then fed TERRA simulated planets to test how efficiently the software detects Earth-size planets.

After carefully measuring the fraction of planets missed by TERRA, the team corrected for this and then plugged in real Kepler observations freely available on the Internet. They identified 119 Earth-like planets ranging in size from nearly six times the diameter of Earth to the diameter of Mars. Thirty-seven of these planets were not identified in previous Kepler reports.

The analysis confirmed that the number of planets increases as the size decreases, which Howard and the Kepler team reported last year. Perhaps 1 percent of stars have planets the size of Jupiter, while 10 percent have planets the size of Neptune.

Adapted from information issued by the University of California, Berkeley.

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