Spiral, elliptical, irregular: This image shows an irregular galaxy named IC 10, a member of the Local Group — a collectiongrouping of over 50 galaxies inwithin our cosmic neighbourhood that includes the Milky Way. IC 10 is a remarkable object. It is the closest-known starburst galaxy to us, meaning that it is undergoing a furious bout of star formation fueled by ample supplies of cool hydrogen gas. This gas condenses into vast molecular clouds, which then form into dense knots where pressures and temperatures reach a point sufficient to ignite nuclear fusion, thus giving rise to new generations of stars. As an irregular galaxy, IC 10 lacks the majestic shape of spiral galaxies such as the Milky Way, or the rounded, ethereal appearance of elliptical galaxies. It is a faint object, despite its relative proximity to us — justof 2.2 million light-years. In fact, IC 10 only became known to humankind in 1887, when American astronomer Lewis Swift spotted it during an observing campaign. The small galaxy remains difficult to study even today, because it is located along a line-of-sight which is chock-full of cosmic dust and stars. A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Nikolaus Sulzenauer, and went on to win tenth prize.

Name: IC 10
Type: Local Universe : Galaxy : Type : Irregular
Category: Galaxies
Constellation: Cassiopeia
Distance: 2 million light years
Release date: 17 June 2019, 06:00
Credit: NASA, ESA and F. Bauer

Trillions of stars: This Hubble Picture of the Week shows the spiral galaxy Messier 98, which is located about 45 million light-years away in the constellation of Coma Berenices (Berenice's Hair). It was discovered in 1781 by the French astronomer Pierre Méchain, a colleague of Charles Messier, and is one of the faintest objects in Messier’s astronomical catalogue. Messier 98 is estimated to contain about a trillion of stars, and is full of cosmic dust — visible here as a web of red-brown stretching across the frame — and hydrogen gas. This abundance of star-forming material means that Messier 98 is producing stellar newborns at a high rate; the galaxy shows the characteristic signs of stars springing to life throughout its bright centre and whirling arms. This image of Messier 98 was taken in 1995 with the Wide Field and Planetary Camera 2, an instrument that was installed on the NASA/ESA Hubble Space Telescope from 1993 till 2009. These observations were taken in infrared and visible light as part of a study of galaxy cores within the Virgo Cluster, and feature a portion of the galaxy near the centre.

Name: Messier 98
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Coma Berenices
Distance: 45 million light years
Release date: 24 June 2019, 06:00
Credit: ESA/Hubble & NASA, V. Rubin et al.

In Bloom: This NASA/ESA Hubble Space Telescope Picture of the Week shows bright, colourful pockets of star formation blooming like roses in a spiral galaxy named NGC 972. The orange-pink glow is created as hydrogen gas reacts to the intense light streaming outwards from nearby newborn stars; these bright patches can be seen here amid dark, tangled streams of cosmic dust. Astronomers look for these telltale signs of star formation when they study galaxies throughout the cosmos, as star formation rates, locations, and histories offer critical clues as to how these colossal collections of gas and dust have evolved over time. New generations of stars contribute to — and are also, in turn, influenced by — the broader forces and factors that mould galaxies throughout the Universe, such as gravity, radiation, matter, and dark matter. German-British astronomer William Herschel is credited with the discovery of NGC 972 in 1784. Astronomers have since measured its distance, finding it to be just under 70 million light-years.

Name: NGC 972
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Aries
Distance: 70 million light years
Release date: 1 July 2019, 06:00
Credit: ESA/Hubble, NASA, L. Ho

Galactic Cherry Blossom: The galaxy NGC 1156 resembles a delicate cherry blossom tree flowering in springtime in this Hubble Picture of the Week. The many bright "blooms" within the galaxy are in fact stellar nurseries — regions where new stars are springing to life. Energetic light emitted by newborn stars in these regions streams outwards and encounters nearby pockets of hydrogen gas, causing it to glow with a characteristic pink hue. NGC 1156 is located in the constellation of Aries (The Ram). It is classified as a dwarf irregular galaxy, meaning that it lacks a clear spiral or rounded shape, as other galaxies have, and is on the smaller side, albeit with a relatively large central region that is more densely packed with stars. Some pockets of gas within NGC 1156 rotate in the opposite direction to the rest of the galaxy, suggesting that there has been a close encounter with another galaxy in NGC 1156's past. The gravity of this other galaxy — and the turbulent chaos of such an interaction — could have scrambled the likely more orderly rotation of material within NGC 1156, producing the odd behaviour we see today.

Name: NGC 1156
Type: Local Universe : Galaxy : Type : IrregularLocal Universe : Galaxy : Size : Dwarf
Category: Galaxies
Constellation: Aries
Release date: 8 July 2019, 06:00
Credit: ESA/Hubble, NASA, R. Jansen

A Beautiful Whorl: Galaxies come in many shapes and sizes. One of the key galaxy types we see in the Universe is the spiral galaxy, as demonstrated in an especially beautiful way by the subject of this Hubble Picture of the Week, NGC 2985. NGC 2985 lies roughly over 70 million light years from the Solar System in the constellation of Ursa Major (The Great Bear). The intricate, near-perfect symmetry on display here reveals the incredible complexity of NGC 2985. Multiple tightly-wound spiral arms widen as they whorl outward from the galaxy’s bright core, slowly fading and dissipating until these majestic structures disappear into the emptiness of intergalactic space, bringing a beautiful end to their starry splendour. Over aeons, spiral galaxies tend to run into other galaxies, often resulting in mergers. These coalescing events scramble the winding structures of the original galaxies, smoothing and rounding their shape. These objects possess a beauty all their own, distinct from the spiral galaxies from whence they came.

Name: NGC 2985
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Ursa Major
Distance: 70 million light years
Release date: 15 July 2019, 06:00
Credit: ESA/Hubble & NASA, L. Ho

Up and Over: Every now and then, the NASA/ESA Hubble Space Telescope glimpses a common object — say, a spiral galaxy — in an interesting or unusual way. A sharply angled perspective, such as the one shown in this Picture of the Week, can make it seem as if we, the viewers, are craning our necks to see over a barrier into the galaxy's bright centre. In the case of NGC 3169, this barrier is the thick dust embedded within the galaxy's spiral arms. Cosmic dust comprises a potpourri of particles, including water ice, hydrocarbons, silicates, and other solid material. It has many origins and sources, from the leftovers of star and planet formation to molecules modified over millions of years by interactions with starlight. NGC 3169 is located about 70 million light-years away in the constellation of Sextans (The Sextant). It is part of the Leo I Group of galaxies, which, like the Local Group that houses our home galaxy, the Milky Way, is part of a larger galactic congregation known as the Virgo Supercluster.

Name: NGC 3169
Type: Local Universe : Galaxy : Type : Spiral
Category: Galaxies
Constellation: Sextans
Distance: 70 million light years
Release date: 22 July 2019, 06:00
Credit: ESA/Hubble & NASA, L. Ho