Messier 49 - Elliptical Galaxy in Virgo
M49, discovered and catalogued by Charles Messier in 1771, is an elliptical galaxy. Such a galaxy is composed of dead and dying stars, with no ongoing star-formation. With a characteristic emission of x-rays from the core of the galaxy, the existence of a super-massive black hole has been suggested. There are also two candidates for smaller black holes as well, called stellar-mass black holes. M49 is the first member of the Virgo cluster of galaxies to be discovered.
Top: Wide-Field - Siggi Kohlert
Bottom: Close-Up - Siggi Kohlert
Messier 48 - Open Cluster in Hydra
M48 was discovered and catalogued by the French comet-hunter Charles Messier in 1771. Such an open cluster is relatively young, estimated to about 300 million years. These clusters are the aftermath of star-formation, a violent event that occurs after massive gas clouds contract to create stars. Young stars are akin to a 5 year old - a lot of emotional explosions and violent outbursts (but without the emotion part!). As these clusters age, the biggest and bluest stars die first, leaving a more loosely collected region of redder stars, which appear much more like the background of the night sky. M48 is visible under the darkest skies, so give it a look!
Top: Wide-Field - Palomar Observatory
Bottom: Close-Up - NOAO
Every one of us is, in the cosmic perspective, precious. If a human disagrees with you, let him live. In a hundred billion galaxies, you will not find another.
Jupiter’s Icy Moon Europa: Best Bet for Alien LIfe?
Jupiter’s moon Europa doesn’t look like a particularly inviting place for life to thrive; the icy satellite is nearly 500 million miles (800 million kilometers) from the sun, on average.
But beneath its icy crust lies a liquid ocean with more water than Earth contains. This ocean is shielded from harmful radiation, making Europa one of the solar system’s best bets to host alien life.
That’s one of the reasons Europa is so alluring to scientists. It has all the elements thought to be key for the origin of life: water, energy, and organic chemicals, the carbon-containing building blocks of life, scientists said at an event called “The Lure of Europa,” held here last month.
Image Credit: NASA/JPL/TED Stryk
Messier 47 - Open Cluster in Puppis
M47 was discovered by Giovanni Batista Hodierna before 1654 and catalogued by Charles Messier in 1771. M47 is an open cluster, meaning that it contains young stars with the same age, composition, and distance. It is estimated to be 78 million years old at a distance of about 1,600 light-years. M47 has only 50 or so stars confirmed to be a part of the cluster.
Image: Andrea Tamanti
(I apologise for not providing my usual two images…)
Do not look at stars as bright spots only. Try to take in the vastness of the universe.
Messier 46 - Open Cluster in Puppis
Discovered and catalogued by the French comet-hunter Charles Messier in 1771, M46 is a “very bright, very rich, [and] very large” open cluster. An open cluster forms from a single molecular cloud, which is essentially a massive collection of gas, which condenses to form stars. This means that all of the stars in M46 come from the same origin, have the same chemical composition, and are of the same age. One particular feature of M46 is the small smudge at the top left. This is a planetary nebula which has nothing to do with a planet. Rather, it is the corpse of a dead low-mass star. Our sun will one day become a planetary nebula. Take a look with a some binoculars!
Top: Wide-Field - Cody Peterson
Bottom: Close-Up - N.A.Sharp/NOAO/AURA/NSF
Messier 45 - The Pleiades
Commonly called “the Seven Sisters”, M45 is one of the most well-known night-sky objects ever. Located in the constellation Taurus, M45 has deep historical roots reaching back to early human times. As it is an open cluster, it is a fairly young cluster with same chemical composition, age, and distance. Although it was catalogued by Charles Messier in 1771, it was first telescopically observed by Galileo Galilei in 1610. If you’re looking to see M45, check your local night sky closer to the spring!
Top: Optical - NASA/ESA/AURA/Caltech
Middle:infrared - John Stauffer/Caltech
Bottom: X-Ray - ROSAT
NGC 5189 - Planetary Nebula
Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)
M44 - The Beehive Cluster
Located in the zodiacal constellation Cancer, M44 is a fairly populated open cluster, known since antiquity. It is one of the closest open clusters as well. First observed by Galileo through his telescope, M44 was catalogued by the comet-hunter Charles Messier in 1769. Because M44 will not be easily confused for a comet, it is thought that this addition marks a departure from his original intention of a list of comet-like objects to assist comet-hunters in confirming their targets, to a more general scientific catalogue. Throughout history, it has been referred to be various names: The Manger, Little Cloud, Little Mist, and the Ghost. In 2012, two exoplanets were identified in M44, marking the first time a planet was found orbiting around a star like our own in such a cluster. Unfortunately, they are not likely to be earth-like, but rather massive gas giants like the planet Jupiter. Look during the springtime!
Top: Wide-Field - Sven Kohle/Till Credner
Bottom: Close-Up - Bob Franke
it is the mark of an educated mind to be able to entertain a thought without accepting it
"Smoking Gun" - Evidence for Theory that Saturn’s Collapsing Magnetic Tail Causes Auroras
University of Leicester researchers have captured stunning images of Saturn’s auroras as the planet’s magnetic field is battered by charged particles from the Sun.
The team’s findings provide a “smoking gun” for the theory that Saturn’s auroral displays are often caused by the dramatic collapse of its “magnetic tail”.
Just like comets, planets such as Saturn and the Earth have a “tail” – known as the magnetotail – that is made up of electrified gas from the Sun and flows out in the planet’s wake.
When a particularly strong burst of particles from the Sun hits Saturn, it can cause the magnetotail to collapse, with the ensuing disturbance of the planet’s magnetic field resulting in spectacular auroral displays. A very similar process happens here on Earth.
We’re machines for turning caffeine into physics
Nima Arkani-Hamed (at a screening of Particle Fever)