Starship Asterisk*

Credit: ESA/Hubble & NASA, K. Stapelfeldt

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In this image the NASA/ESA Hubble Space Telescope has captured the smoking gun of a newborn star, the Herbig–Haro objects numbered 7 to 11 (HH 7–11). These five objects, visible in blue in the top centre of the image, lie within NGC 1333, a reflection nebula full of gas and dust found about a thousand light-years away from Earth.

Herbig-Haro objects like HH 7–11 are transient phenomena. Travelling away from the star that created them, at a speed of up to 250 000 kilometres per hour they disappear into nothingness within a few tens of thousands of years. The young star that is the source of HH 7-11 is called SVS 13 and all five objects are moving away from SVS 13 toward the upper left. The current distance between HH 7 and SVS 13 is about 20 000 times the distance between Earth and the Sun.

Herbig–Haro objects are formed when jets of ionised gas ejected by a young star collide with nearby clouds of gas and dust at high speeds. The Herbig-Haro objects visible in this image are no exception to this and were formed when the jets from the newborn star SVS 13 collided with the surrounding clouds. These collisions created the five brilliant clumps of light within the reflection nebula.

Image Credit: Petr Horálek / ESO

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This panorama of the landscape around ESO’s Paranal Observatory, located in the Chilean Atacama Desert, was taken by ESO Photo Ambassador Petr Horálek.

Captured at dusk, it shows the moment just after sunset, when the the sky is painted in beautiful colours of yellow, orange, red, even blue-purple, and the reddish hues of the desert below are enhanced by the soft light. This time of day is known as twilight, but is also referred to as blue hour (named for the colour of the sky). The unique and ethereal quality of the light during blue hour has also earned it the nickname of “sweet light” amongst artists and photographers.

The planet Venus stands out against the pink of the sky in the very centre of the image, while the Very Large Telescope (VLT) rests atop the mountain on the right, Cerro Paranal. The Andromeda Galaxy is faintly visible to the right of the four giant 8.2-metre-diameter VLT Unit Telescopes, recognisable by its iconic oval shape. Andromeda is a Northern sky object, barely visible above the safety pointing limits of the telescopes at Paranal.

bystander wrote: ↑Tue Dec 25, 2018 12:14 am Climbing the Cosmic Distance Ladder
ESA Hubble Picture of the Week | 208 Dec 24

Credit: ESA/Hubble, & NASA

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This image from the NASA/ESA Hubble Space Telescope reveals an ancient, glimmering ball of stars called NGC 1466. It is a globular cluster — a gathering of stars all held together by gravity — that is slowly moving through space on the outskirts of the Large Magellanic Cloud, one of our closest galactic neighbours.

NGC 1466 certainly is one for extremes. It has a mass equivalent to roughly 140 000 Suns and an age of around 13.1 billion years, making it almost as old as the Universe itself. This fossil-like relic from the early Universe lies some 160 000 light-years away from us.

Nestled within this ancient time capsule are 49 known RR Lyrae variable stars, which are indispensable tools for measuring distances in the Universe. These variable stars have well-defined luminosities, meaning that astronomers know the total amount of energy they emit. By comparing this known luminosity to how bright the stars appear in the sky, their distance can be easily calculated. Astronomical objects such as this are known as standard candles, and are fundamental to the so-called cosmic distance ladder.

Credit: ESA/Hubble, & NASA

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This image from the NASA/ESA Hubble Space Telescope reveals an ancient, glimmering ball of stars called NGC 1466. It is a globular cluster — a gathering of stars all held together by gravity — that is slowly moving through space on the outskirts of the Large Magellanic Cloud, one of our closest galactic neighbours.

NGC 1466 certainly is one for extremes. It has a mass equivalent to roughly 140 000 Suns and an age of around 13.1 billion years, making it almost as old as the Universe itself. This fossil-like relic from the early Universe lies some 160 000 light-years away from us.

Nestled within this ancient time capsule are 49 known RR Lyrae variable stars, which are indispensable tools for measuring distances in the Universe. These variable stars have well-defined luminosities, meaning that astronomers know the total amount of energy they emit. By comparing this known luminosity to how bright the stars appear in the sky, their distance can be easily calculated. Astronomical objects such as this are known as standard candles, and are fundamental to the so-called cosmic distance ladder.

Credit: G. Hüdepohl (atacamaphoto.com)/ESO

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Few people have ever viewed the Moon through a telescope as monumental as ESO’s Very Large Telescope (VLT). Astronomers at Paranal Observatory in Chile recently enjoyed this unique opportunity when one of the telescope’s instruments, VIMOS (VIsible Multi-Object Spectrograph), was decommissioned to free up a space at the UT3 telescope for the upcoming CRIRES+ (the CRyogenic InfraRed Echelle Spectrograph Upgrade Project).

VIMOS was astonishingly productive; the spectrograph studied thousands of distant galaxies seen at a time when the Universe was only at a third of its current age, and mapped their distribution and physical properties. The sensitive instruments used by the VLT, including VIMOS, are designed to image dim objects billions of light-years away, and therefore objects as near and bright as our planet’s moon easily completely saturate them with far too much light. But when VIMOS was decommissioned after 16 years of service, the astronomers stationed at Paranal took advantage of the unusual opportunity to utilise a telescope focal station with no instrument attached.

Instead of looking into deep space, they pointed and focused UT3, one of the VLT’s Unit Telescopes — the VLT has four, each with a mirror measuring 8.2 metres across — on the Moon. To create this mesmerising image, the twilight Moon was projected onto a semi-transparent screen, resulting in an intricately detailed display of the myriad crags and craters scattered across its surface. This incredible view was enjoyed by numerous astronomers including Stefan Ströbele, the Adaptive Optics engineer seen in this image.