Alberta scientists studying births of stars and galaxies


Researchers inspect the telescope of the Herschel Space Observatory. The telescope will carry the largest mirror ever flown in space. It is 3.5 meters in diameter. Photo courtesy of European Space Agency

By Kevin Rushworth

Story from CJ CONNECT

Alongside an international team of scientists, Alberta researchers are using the launched Herschel Space Observatory to study the birth of stars, planets and galaxies.

By using advanced instruments aboard the observatory, scientists are photographing the cosmos at infrared and sub millimetre wavelengths, revolutionizing how far human beings can look into deep space.

The observatory orbits with the Earth and Sun one-and-a-half-million kilometres away from life on our planet. After ten years of development, the largest space telescope ever sent into orbit was successfully launched by the European Space Agency from French Guiana in May of 2009. Its primary mirror measures 3.5 metres in diameter.

Rene Plume, an associate University of Calgary professor of astronomy, is part of the international team studying the earliest stages of galaxies, some of which were created one billion years after the Big Bang.  With the Herschel Space Observatory, researchers are looking to learn when the first generation of stars formed and what they were like, Plume said.

“By looking at the (space) dust, you are actually looking at the pristine material,” he said. “It is the material out of which the planets would have had to form. You are looking at the earliest stages of the process.”

Regions of space with more interstellar material have stronger gravitational pulls causing material to be sucked in, Plume explained.

“As this material (gets) pulled in, it begins to coagulate,” he said. “It begins to smash against one another and stick and form large particles of dust and then pebbles, boulders, asteroids and then planets.”

Plume said interstellar space is more than 250 degrees below zero or 20 to 50 degrees Kelvin. Solid objects emit colourful radiation according to their temperature, he said. Plume added that objects with temperatures equalling that of deep space emit much of their radiation in the infrared and sub millimetre wavelengths which Herschel’s instruments use.

With the observatory, Plume said scientists are watching stars as they are formed in giant clouds of dust and gas. If looked at with optical light, he said, these clouds would be dark patches in the sky.

“There could be a young star embedded within (the cloud) and you wouldn’t know it,” Plume said. “In the infrared and sub millimetre (wavelengths), that radiation formed in the centre coming from the embryonic star can actually travel all the way through the cloud and we can see it.”

He likened the young star stuck in the gas cloud to an individual in a room with no windows and a closed door. Plume said the only items they held were a flash light and a cell phone.

“You can flash the light all you wanted, but nobody would see you because the light from the flashlight wouldn’t make it out (of the room),” he said. “(But), you could call your friend on your cell phone to let you out of the room because that cell phone operates at radio waves. Radio waves can penetrate through walls.”

Russ Taylor, a U of C astrophysics professor, said infrared and long wavelength radio waves give a much different picture of deep space than optical light.

“The best way to look at it is that the hotter something is, the more optical light it gives out,” Taylor said. “When we look at the universe with our eyes, we see the very hot parts (which are) the stars.”

He said black spaces between stars are filled with material too cold to see with our eyes. The infrared wavelengths that Herschel views the galaxy with are used for search and rescue missions on Earth, Taylor said.

However, Plume said that when scientists observe space using different wavelengths, they see a completely altered sky.

“If you were able to strap on a pair of binoculars that would allow you to look at the sky in radio wavelengths, you would see emission everywhere,” he said. “The galaxy would be glowing brightly from all the atomic, molecular gas and dust that is out there.”

With observatory instruments, Plume, and over 100 team members are working to map

Cold gas shown in the constellation of Southern Cross. Photo courtesy of ESA and the SPIRE & PACS consortia

the Milky Way Galaxy. He is one of ten international co-ordinators for the HiGal project or the Herschel Infrared Galactic Plane Survey.

Although galaxy surveys have been completed using far radio, optical and near infrared wavelengths, Plume said the galaxy is poorly understood at far infrared and sub millimetre. At these wavelengths, he said scientists can watch material coming together to form stars and as those young stars turn on.

Plume said researchers have the ability to find every star forming region in the Milky Way using the survey—including places where rare stars 10 times the mass of our sun are created. Out of 100 billion stars in the galaxy, Plume estimated that there are 2,000 massive stars. Using the observatory, their goal is to find an embryonic massive star in our Milky Way Galaxy.

“We will be able to study it from a statistical perspective,” he said. “That’s all we can do because it takes hundreds of thousands to millions of years for a cloud to collapse under the force of gravity and for the interior to become hot enough for nuclear processes to begin.”

Using the galactic survey, Plume and the international team are looking for stars in different stages of their lifetimes so they can learn how stars are born and then die.

Taylor said there is a missing link in the understanding of both star formation processes and the evolution of the universe. He hopes that research done through the observatory will start to fill it in.

“There’s been a lot of understanding about the final details about (what happens) when you have a big ball of matter together (and) how it evolves into a star,” he said. “But the process which actually drives that (and takes) the matter when the universe was created and creates the conditions for forming stars is not really understood.”

Three main instruments—HIFI,PACS and SPIRE— are aboard the Herschel Space Observatory. HiFi, or the Heterodyne Instrument for the Far-Infrared, is a spectrometer, a device which spreads light out over frequencies to see its composition.

“It’s so high resolution that we can actually see these clouds of gas rotating in space,” Plume said. “We can see them collapsing under the force of gravity.”

On the other hand, Plume said that PACS, a Photodetector Array Camera and Spectrometer, and SPIRE, otherwise known as the Spectral and Photometric Imaging Receiver, are essentially infrared cameras.  Plume said the images being produced from Herschel are spectacular and that they provide scientists with details regarding the structure of space, galaxies and the formation processes of stars and planets.

David Naylor, a University of Lethbridge physics and astronomy professor, was one of three individuals who designed the SPIRE instrument—a device that provides the infrared camera with colour vision.

Before the launch date, he said years were spent testing the instrument at the Rutherford Appleton Laboratory in Oxford, England. Naylor said he has spent his entire life career so far working with SPIRE. As the lead scientist in Canada on the project, he was the only Canadian invited to the launch in French Guiana.

“As we approached launch, it was extremely emotional,” he said. “You realized that this was it; there was no turning back. It was either going to be extremely successful or a catastrophic failure if something went wrong.”

Although he called the launch a once-in-a-lifetime experience, tension mounted as the day approached. Naylor said it was nerve-wracking to have both a billion dollar space mission and the SPIRE instrument above 700,000 kilograms of fuel.

“When the launch started, there was not a dry eye in the place,” Naylor remembered. “I was surrounded by VIPs, ministers, dignitaries and fellow scientists. You spend your whole life on this and it matters. I was overcome with emotion, as was everybody. My eyes were wet and some were physically crying.”

Russ Taylor said, with new observatories, scientists always have ideas of what they are going to see, but that those ideas are always based off what they already know.

“Every time you take a big step in technology and observe the universe in a different way that you’ve never done before, there’s always things you wouldn’t expect,” he said. “It’s just the nature of the world. It’s stranger than we can imagine.”

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