Flux RSS d'astronomie

ESA Top Multimedia

ESA Top Multimedia

Spiral snapshot

The luminous heart of the galaxy M61 dominates this image, framed by its winding spiral arms threaded with dark tendrils of dust. As well as the usual bright bands of stars, the spiral arms of M61 are studded with ruby-red patches of light. Tell-tale signs of recent star formation, these glowing regions lead to M61’s classification as a starburst galaxy.

Though the gleaming spiral of this galaxy makes for a spectacular sight, one of the most interesting features of M61 lurks unseen at the centre of this image. As well as widespread pockets of star formation, M61 hosts a supermassive black hole more than 5 million times as massive as the Sun.

M61 appears almost face-on, making it a popular subject for astronomical images, even though the galaxy lies more than 52 million light-years from Earth. This particular astronomical image incorporates data from not only Hubble, but also the FORS camera at the European Southern Observatory’s Very Large Telescope, together revealing M61 in unprecedented detail. This striking image is one of many examples of telescope teamwork — astronomers frequently combine data from ground-based and space-based telescopes to learn more about the Universe.

Earth from Space: Bucharest

In this week's edition of the Earth from Space programme, Copernicus Sentinel-2  takes us over Bucharest – the capital and largest city of Romania.
See also Bucharest, Romania to download the image.

Return to the Veil Nebula

This Picture of the Week revisits the Veil Nebula, a popular subject for Hubble images! This object was featured in a previous Hubble photo release, but now new processing techniques have been applied, bringing out fine details of the nebula’s delicate threads and filaments of ionised gas.

To create this colourful image, observations taken by Hubble's Wide Field Camera 3 instrument through 5 different filters were used. The new post-processing methods have further enhanced details of emissions from doubly ionised oxygen (seen here in blues), ionised hydrogen and ionised nitrogen (seen here in reds).

The Veil Nebula lies around 2100 light-years from Earth in the constellation of Cygnus (The Swan), making it a relatively close neighbour in astronomical terms. Only a small portion of the nebula was captured in this image.

The Veil Nebula is the visible portion of the nearby Cygnus Loop, a supernova remnant formed roughly 10 000 years ago by the death of a massive star. The Veil Nebula’s progenitor star — which was 20 times the mass of the Sun — lived fast and died young, ending its life in a cataclysmic release of energy. Despite this stellar violence, the shockwaves and debris from the supernova sculpted the Veil Nebula’s delicate tracery of ionised gas — creating a scene of surprising astronomical beauty.

Earth from Space: Easter egg hunt

With Easter right around the corner, this week's edition of the Earth from Space programme features four egg-shaped buildings visible from space as captured by the Copernicus Sentinel-2 mission.

See also Easter egg hunt to download the images

Earth from Space: Gariep Dam, South Africa

In this week's edition of the Earth from Space programme, the Copernicus Sentinel-2 mission takes us over the Gariep Dam, the largest dam in South Africa.
See also Gariep Dam, South Africa to download the image.

A peculiar sight

This week’s Hubble/ESA Picture of the Week features NGC 7678 — a galaxy located approximately 164 million light-years away in the constellation of Pegasus (The Winged Horse). With a diameter of around 115 000 light-years, this bright spiral galaxy is a similar size to our own galaxy (the Milky Way), and was discovered in 1784 by the German-British astronomer William Herschel.

The Atlas of Peculiar Galaxies is a catalogue which was produced in 1966 by the American astronomer Halton Arp. NGC 7678 is among the 338 galaxies presented in this catalogue, which organises peculiar galaxies according to their unusual features. Catalogued here as Arp 28, this galaxy is listed together with six others in the group “spiral galaxies with one heavy arm”.  

A flash of life

Located around 5000 light-years away in the constellation of Cygnus (The Swan), Abell 78 is an unusual type of planetary nebula. 

After exhausting the nuclear fuel in their cores, stars with a mass of around 0.8 to 8 times the mass of our Sun collapse to form dense and hot white dwarf stars. As this process occurs, the dying star will throw off its outer layers of material, forming an elaborate cloud of gas and dust known as a planetary nebula. This phenomenon is not uncommon, and planetary nebulae are a popular focus for astrophotographers because of their often beautiful and complex shapes. However, a few like Abell 78 are the result of a so-called “born again” star. 

Although the core of the star has stopped burning hydrogen and helium, a thermonuclear runaway at its surface ejects material at high speeds. This ejecta shocks and sweeps up the material of the old nebula, producing the filaments and irregular shell around the central star seen in this Picture of the Week, which features data from Hubble’s Wide Field Camera 3 and PANSTARSS.

Earth from Space: Amazon rainforest

In this week's edition of the Earth from Space programme, the Copernicus Sentinel-2 mission takes us over part of the Amazon rainforest in the Amazonas – the largest state in Brazil.
See also Amazon rainforest to download the image.

Infant stars in Orion

These four images taken by the NASA/ESA Hubble Space Telescope reveal the chaotic birth of stars in the Orion complex, the nearest major star-forming region to Earth.

The snapshots show fledgling stars buried in dusty gaseous cocoons announcing their births by unleashing powerful winds, as well as pairs of spinning, lawn-sprinkler-style jets shooting off in opposite directions. Near-infrared light pierces the dusty region to unveil details of the birthing process.

The stellar outflows are carving out cavities within the gas cloud, composed of hydrogen gas. This relatively brief birthing stage lasts about 500 000 years.

Although the stars themselves are shrouded in dust, they emit powerful radiation, which strikes the cavity walls and scatters off dust grains, illuminating in infrared light the gaps in the gaseous envelopes. Astronomers found that the cavities in the surrounding gas cloud sculpted by a forming star’s outflow did not grow regularly as they matured, as theories propose.

The young stars in these images are just a subset of an ambitious study of 304 developing stars, the largest-ever to date. Researchers used data previously collected from Hubble as well as the NASA Spitzer Space Telescope and the European Space Agency's Herschel Space Telescope.

The protostars were photographed in near-infrared light by Hubble's Wide Field Camera 3. The images were taken 14 November 2009, and 25 January, 11 February, and 11 August 2010.

Through the clouds

Nestled amongst the vast clouds of star-forming regions like this one lie potential clues about the formation of our own Solar System. 

This week’s NASA/ESA Hubble Space Telescope Picture of the Week features AFGL 5180, a beautiful stellar nursery located in the constellation of Gemini (The Twins). 

At the centre of the image, a massive star is forming and blasting cavities through the clouds with a pair of powerful jets, extending to the top right and bottom left of the image. Light from this star is mostly escaping and reaching us by illuminating these cavities, like a lighthouse piercing through the storm clouds.

Stars are born in dusty environments and although this dust makes for spectacular images, it can prevent astronomers from seeing stars embedded in it. Hubble’s Wide Field Camera 3 (WFC3) instrument is designed to capture detailed images in both visible and infrared light, meaning that the young stars hidden in vast star-forming regions like AFGL 5180 can be seen much more clearly. 

Earth from Space: Strait of Gibraltar

This week's edition of the Earth from Space programme features a Copernicus Sentinel-2 image of the Strait of Gibraltar.

See also Strait of Gibraltar to download the image.

Hubble solves mystery of monster star's dimming

If placed in the middle of our solar system, the star VY Canis Majoris would engulf all the planets out to Saturn's orbit. This monster, appropriately called a red hypergiant, is as bright as 300,000 Suns. Yet it is so far away that, 200 years ago, it could be seen only as a faint star in the winter constellation of the Great Dog. Since then, it has faded and is no longer visible to the naked eye. Astronomers used the NASA/ESA Hubble Space Telescope to get a close-up look at the star and discovered the reason for the dimming. The star is expelling huge clouds of dust in the final stages of its life. Eventually, the bloated star may explode as a supernova, or may simply collapse and form a black hole.

This zoom into VY Canis Majoris is a combination of Hubble imaging and an artist's impression. The left panel is a multicolor Hubble image of the huge nebula of material cast off by the hypergiant star. This nebula is approximately 300 billion kilometres across. 

The middle panel is a close-up Hubble view of the region around the star. This image reveals close-in knots, arcs, and filaments of material ejected from the star as it goes through its violent process of casting off material into space. VY Canis Majoris is not seen in this view, but the tiny red square marks the location of the hypergiant, and represents the diameter of the solar system out to the orbit of Neptune, which is 5.5 billion miles across. 

The final panel is an artist's impression of the hypergiant star with vast convection cells and undergoing violent ejections. VY Canis Majoris is so large that if it replaced the Sun, the star would extend for hundreds of millions of miles, to between the orbits of Jupiter and Saturn.

Earth from Space: Galápagos Islands

In this week's edition of the Earth from space programme, the Copernicus Sentinel-2 mission takes us over the Galápagos Islands – a volcanic archipelago situated some 1000 km west of Ecuador in the Pacific Ocean.

See also Galápagos Islands to download the image.

Big, beautiful and blue

NGC 2336 is the quintessential galaxy — big, beautiful and blue — and it is captured here by the NASA/ESA Hubble Space Telescope. The barred spiral galaxy stretches an immense 200 000 light-years across and is located approximately 100 million light years away in the northern constellation of Camelopardalis (The Giraffe).

Its spiral arms are glittered with young stars, visible in their bright blue light. In contrast, the redder central part of the galaxy is dominated by older stars.

NGC 2336 was discovered in 1876 by German astronomer Wilhelm Tempel, using a 28-centimetre telescope. This Hubble image is so much better than the view Tempel would have had — Hubble’s main mirror is 2.4 metres across, nearly ten times the size of the telescope Tempel used. In 1987, NGC 2336 experienced a Type-Ia supernova, the only observed supernova in the galaxy since its discovery 111 years earlier.

Earth from Space: Vancouver

In this week's edition of the Earth from Space programme, the Copernicus Sentinel-2 mission takes us over Vancouver – the third largest city in Canada.
See also Vancouver, Canada to download the image.

Earth from Space: Lusaka

In this week's edition of the Earth from Space programme, the Copernicus Sentinel-2 mission takes us over Lusaka – the capital and largest city of Zambia.

See also Lusaka, Zambia to download the image.

Earth from Space: Valentine Island

For Valentine's day, this week's edition of the Earth from Space programme features a Copernicus Sentinel-2 image of Valentine Island in northern Western Australia.
See also Valentine Island, Australia to download the image.

Earth from Space: Japan in bloom

In this week's edition of the Earth from Space programme, the Copernicus Sentinel-2 mission takes us over the algal blooms swirling around the Pacific Ocean, just off the coast of Japan.

See also Japan in bloom to download the image.

Earth from Space: Lake Titicaca

Ahead of World Wetlands Day, this week's edition of the Earth from Space programme features a Copernicus Sentinel-2 image of Lake Titicaca – one of the largest lakes in South America and a designated Ramsar site of International Importance.
See also Lake Titicaca to download the image.

Revenir