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Planck’s new view of the cosmic theatre

Copyright ESA

The first scientific results from ESA’s Planck mission were released at a press briefing today in Paris. The findings focus on the coldest objects in the Universe, from within our Galaxy to the distant reaches of space.

If William Shakespeare were an astronomer living today, he might write that “All the Universe is a stage, and all the galaxies merely players.” Planck is bringing us new views of both the stage and players, revealing the drama of the evolution of our Universe.

Following the publication by ESA of the first full-sky Planck image in July last year, today sees the release of the first scientific results from the mission.

These results are being presented by the Planck Collaboration at a major scientific conference in Paris this week, based on 25 papers submitted to the journal Astronomy & Astrophysics.

The basis of many of these results is the Planck mission’s ‘Early Release Compact Source Catalogue’, the equivalent of a cast list.

Drawn from Planck’s continuing survey of the entire sky at millimetre and submillimetre wavelengths, the catalogue contains thousands of very cold, individual sources which the scientific community is now free to explore.

“This is a great [...]

Galaxies Come Together after Billions of Years

Imagine finding a living dinosaur in your backyard. Astronomers have found the astronomical equivalent of prehistoric life in our intergalactic back yard: a group of small, ancient galaxies that has waited 10 billion years to come together. These “late bloomers” are on their way to building a large elliptical galaxy.

Such encounters between dwarf galaxies are normally seen billions of light-years away and therefore occurred billions of years ago. But these galaxies, members of Hickson Compact Group 31, are relatively nearby, only 166 million light-years away.

New images of these galaxies by NASA’s Hubble Space Telescope offer a window into what commonly happened in the universe’s formative years when large galaxies were created from smaller building blocks. The Hubble observations have added important clues to the story of this interacting foursome, allowing astronomers to determine when the encounter began and to predict a future merger.

Astronomers know the system has been around for a while because the oldest stars in a few of its ancient globular clusters are about 10 billion years old. The encounter, though, has been going on for about a few hundred million years, the blink of an eye in cosmic history. Everywhere the astronomers [...]

Hubble highlights two galaxies that are losing it

Hubble highlights two galaxies that are losing it

Copyright ESA

Newly released images, taken by the Hubble Space Telescope before the recent Servicing Mission, highlight the ongoing drama in two galaxies in the Virgo Cluster affected by a process known as ‘ram pressure stripping’, which can result in peculiar-looking galaxies.

An extremely hot X-ray-emitting gas known as the intra-cluster medium lurks between galaxies within clusters. As galaxies move through this intra-cluster medium, strong winds rip through galaxies distorting their shape and even halting star formation.

Ram pressure is the drag force that results when something moves through a fluid – much like the wind you feel in your face when bicycling, even on a still day – and occurs in this context as galaxies orbiting about the centre of the cluster move through the intra-cluster medium, which then sweeps out gas from within the galaxies.

The spiral galaxy NGC 4522 is located some 60 million light-years from Earth and it is a spectacular example of a spiral galaxy currently being stripped of its gas content.

Part of the Virgo galaxy cluster, its rapid motion within the cluster results in strong winds across the galaxy as the gas within is left behind. Scientists estimate that the galaxy is [...]

Herschel images promise bright future

Herschel images promise bright future

Copyright ESA

Herschel has carried out the first test observations with all its instruments, with spectacular results. Galaxies, star-forming regions and dying stars comprised the telescope’s first targets. The instruments provided spectacular data on their first attempt, finding water and carbon and revealing dozens of distant galaxies.

These observations show that Herschel’s instruments are working beyond expectations. They promise a mission of rich discoveries for waiting astronomers.

On 24 June, Herschel’s Spectral and Photometric Imaging Receiver (SPIRE) was trained on two galaxies for its first look at the Universe. The galaxies showed up prominently, providing astronomers with their best images yet at these wavelengths, and revealing other, more distant galaxies in the background of the images.

The pictures below show galaxies M66 and M74 at a wavelength of 250 microns, longer than any previous infrared space observatory, but still the shortest SPIRE wavelength.

SPIRE is designed to look at star formation in our own Galaxy and in nearby galaxies. It will also search for star-forming galaxies in the very distant Universe. Because these galaxies are so far away, their light has taken a very long time to reach us, so by detecting them we are looking into the past [...]

Hubble finds hundreds of young galaxies in the early Universe

hubble-finds-hundreds-of-young-galaxies-in-the-early-universe

Copyright ESA

Astronomers analysing two of the deepest views of the cosmos made with the NASA/ESA Hubble Space Telescope have uncovered a gold mine of galaxies, more than 500, that existed less than a thousand million years after the Big Bang.

These galaxies thrived when the cosmos was less than 7 percent of its present age (13.7 thousand million years). This sample represents the most comprehensive compilation of galaxies in the early Universe, researchers said.

The discovery is scientifically invaluable for understanding the origin of galaxies, considering that just a decade ago early galaxy formation was largely uncharted territory.

Astronomers had never seen a galaxy that existed when the Universe was a thousand million years old, so finding 500 in a Hubble survey is a significant leap forward for cosmologists.

The galaxies unveiled by Hubble are smaller than today’s giant galaxies and very bluish in colour, indicating they are ablaze with star birth. The images appear red because of the galaxies’ tremendous distance from Earth. The blue light from their young stars took nearly 13 thousand million years to arrive at Earth. During the journey, the blue light was shifted to red light due to the expansion of space.

“Finding [...]