Space Pic of the Day

[Hobbes]

Saturn’s satellite Dione is less than half the size of our moon, and it orbits a planet which features a radius nine times that of Earth. It’s a stark contrast in size that’s beautifully conveyed in a picture recently captured by the Cassini space probe.
This gorgeous image was taken by Cassini at a distance of 618,000 miles (994,000 kilometers) from Saturn on May 27, 2015.

Saturn appears hazy compared to Dione owing to the image being acquired via a wavelength absorbed by methane. Dione, unlike Saturn, does not experience methane absorption, so the light simply bounces off its icy surface.

 

[Hobbes]

The arrangement of the spiral arms in the galaxy Messier 63, seen here in a new image from the NASA/ESA Hubble Space Telescope, recall the pattern at the centre of a sunflower. So the nickname for this cosmic object — the Sunflower Galaxy — is no coincidence.

Discovered by Pierre Mechain in 1779, the galaxy later made it as the 63rd entry into fellow French astronomer Charles Messier’s famous catalogue, published in 1781. The two astronomers spotted the Sunflower Galaxy’s glow in the small, northern constellation Canes Venatici (the Hunting Dogs). We now know this galaxy is about 27 million light-years away and belongs to the M51 Group — a group of galaxies, named after its brightest member, Messier 51, another spiral-shaped galaxy dubbed the Whirlpool Galaxy.

Galactic arms, sunflowers and whirlpools are only a few examples of nature’s apparent preference for spirals. For galaxies like Messier 63 the winding arms shine bright because of the presence of recently formed, blue–white giant stars, readily seen in this Hubble image.

 

[Hobbes]

This new NASA/ESA Hubble Space Telescope shows Messier 96, a spiral galaxy just over 35 million light-years away in the constellation of Leo (The Lion). It is of about the same mass and size as the Milky Way. It was first discovered by astronomer Pierre Méchain in 1781, and added to Charles Messier’s famous catalogue of astronomical objects just four days later.

The galaxy resembles a giant maelstrom of glowing gas, rippled with dark dust that swirls inwards towards the nucleus. Messier 96 is a very asymmetric galaxy; its dust and gas is unevenly spread throughout its weak spiral arms, and its core is not exactly at the galactic centre. Its arms are also asymmetrical, thought to have been influenced by the gravitational pull of other galaxies within the same group as Messier 96.

This group, named the M96 Group, also includes the bright galaxies Messier 105 and Messier 95, as well as a number of smaller and fainter galaxies. It is the nearest group containing both bright spirals and a bright elliptical galaxy (Messier 105).

Credit:

ESA/Hubble & NASA and the LEGUS Team

 

[Hobbes]

Shown here in a new image taken with the Advanced Camera for Surveys (ACS) on board the NASA/ESA Hubble Space Telescope, is the globular cluster NGC 1783. This is one of the biggest globular clusters in the Large Magellanic Cloud, a satellite galaxy of our own galaxy, the Milky Way, in the southern hemisphere constellation of Dorado.

First observed by John Herschel in 1835, NGC 1783 is nearly 160 000 light-years from Earth, and has a mass around 170 000 times that of the Sun.

Globular clusters are dense collections of stars held together by their own gravity, which orbit around galaxies like satellites. The image clearly shows the symmetrical shape of NGC 1783 and the concentration of stars towards the centre, both typical features of globular clusters.

By measuring the colour and brightness of individual stars, astronomers can deduce an overall age for a cluster and a picture of its star formation history. NGC 1783 is thought to be under one and a half billion years old — which is very young for globular clusters, which are typically several billion years old. During that time, it is thought to have undergone at least two periods of star formation, separated by 50 to 100 million years.

This ebb and flow of star-forming activity is an indicator of how much gas is available for star formation at any one time. When the most massive stars created in the first burst of formation explode as supernovae they blow away the gas needed to form further stars, but the gas reservoir can later be replenished by less massive stars which last longer and shed their gas less violently. After this gas flows to the dense central regions of the star cluster, a second phase of star formation can take place and once again the short-lived massive stars blow away any leftover gas. This cycle can continue a few times, at which time the remaining gas reservoir is thought to be too small to form any new stars.

A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Judy Schmidt.

Credit:

ESA/Hubble & NASA

 

[dennishoddy]

Somewhere among all of those planets, there has to be life.

 

[Hobbes]

Astronaut Scott Kelly is halfway through a 12 month stint on the International Space Station.
Here are some pictures he took during the first 6 months so far.

June 27, 2015: A hint of red and green aurora tint the planet while the International Space Station’s solar panels dominate the foreground. Image credit: NASA/Scott Kelly

July 19, 2015: The cays of the Bahamas. Image credit: NASA/Scott Kelly

August 10, 2015: The western United States at night with city glow (yellow-orange) and scattered lightning in thunderstorms (white-blue). Image credit: NASA/Scott Kelly

May 8, 2015: A single ridge splits the landscape and casts a deep shadow, evidence of a torn planet and a traumatic past. Image credit: NASA/Scott Kelly

June 9, 2015: Green fields tile Southeast Asia. Image credit: NASA/Scott Kelly

July 19, 2015: The Earth, Venus, Jupiter, and the Moon. Image credit: NASA/Scott Kelly

July 25, 2015: Night over Japan, with the Soyuz spacecraft connected to the Mini Research Module 1 (MRM1) and a Progress cargo tug visible in the foreground. Image credit: NASA/Scott Kelly

 

[GunSlingingPlatypus]

These are awesome pics!!! Thanks for sharing them.

 

[SoonerP226]

July 25, 2015: Night over Japan, with the Soyuz spacecraft connected to the Mini Research Module 1 (MRM1) and a Progress cargo tug visible in the foreground. Image credit: NASA/Scott Kelly

Cool pic. The way they trail down to the sea through the valleys, the lights look like lava flows.

 

[Junior Bonner]

Nice pics. Pretty.

 

[n423]

beautiful pics ...