Saturn And Its Moons

stars, mercury, and solar corona, photographed by stereo a, january 2009.

27 frames, photographed over 36 hours, 2nd-3rd january. the sun is out of frame right.

image credit: nasa/stereo. animation: ageofdestruction.

Two moons of Uranus: Titania and Oberon. Both moons were discovered by William Herschel in 1787.

Credit: NASA/JPL

Astronomy Photo of the Day: 5/30/15 — Vividly Blue NGC 7822

This beautifully blue image comes from Manuel Fernández Suarez—an award winning astrophotographer. It provides a window into the heart of a stellar nursery, found approximately 3,000 light-years from Earth in the Cepheus constellation.

Called NGC 7822, it lurks on the outskirts of a behemoth molecular cloud (one of the largest in our galaxy), and contains numerous features, like the star cluster known as Berkeley 59, along with one of the hottest stars in our local part of the galaxy—called BD+66 1673 (there, temperatures can exceed 45,000 K).

As we noted before, “The region, formally known as NGC 7822, contains hundreds of newborn stars that are leaving their own mark on the interstellar material surrounding them, seeding it with heavy elements that will ultimately collapse to give life to a new generation of stars. These same stars are also slowly chipping away at some of the material, they in turn, give it its distinct shape and its designation as an emission nebula.”

Sources & Other Resources: http://bit.ly/1LPOf5M

Image Credit: Manuel Fernández Suarez

The Spanish Dancer and her supernova by strongmanmike2002 on Flickr.

Grand Spiral Galaxy  - M 100

Known as a grand design spiral galaxy, M100 is a large galaxy of over 100 billion stars with spiral arms that are like our own Milky Way Galaxy. This Hubble Space Telescope image of M100 was made in 2009 and reveals bright blue star clusters and intricate winding dust lanes which are hallmarks of this class of galaxies. Studies of variable stars in M100 have played an important role in determining the size and age of the Universe.

Credit: NASA/APOD

Comas and Tails of Comets The generally unexpected and sometimes spectacular appearance of comets have triggered the interest of many people throughout history. A bright comet can easily be seen with the naked eye. Comets are usually not discovered until after a coma or tail has formed. Depending on the apparent size of the coma or tail, a comet can be very bright. Some comets have a tail extending more than 45˚ on the sky. The earliest records of comet observations date to ~6000BCE in China. The smaller nucleus (rocky body) of a comet, often only a few kilometres in diameter, is usually hidden from view by the large coma, a cloud of gas and dust roughly 10 to the power of 4-10 to the power of 5 km in diameter and not seen with the naked eye, a large hydrogen coma, between 1 and 10 million km in extent, which surrounds the nucleus and visible gas/dust coma. Two tails are often visible, both in the antisolar direction: a curved yellowish dust tail and a straight ion tail, usually of a blue colour. Comets are usually inert at large heliocentric distances and only develop a coma and tails when they get closer to the sun. When the sublimating gas evolves off the surface of a comet’s nucleus, dust is dragged along. The gas and dust form a comet’s coma and hide the nucleus from view. Most comets are discovered after the coma has formed when they are bright enough to be seen with relatively small telescopes. ~ JM Image Credit More Info: Comets, NASA Coma

The Bubble Nebula (NGC 7635) Image Credit: NASA/ESA

Beware of the Big, Bad Wolf

Visible within the center of the Crescent nebula is what’s classified as a Wolf-Rayet star. This star is a staggering 250,000 times brighter than the Sun, 15 times more massive, and 3.3 times larger. Its surface temperature is nearly 70,000° C/ 125,000° F. At just 4.7 million years old, it is already toward the end of it’s life and is shedding its outer envelope, ejecting the equivalent of the Sun’s mass every 10,000 years. Within a few hundred thousand years, it is expected to explode as a supernova.   (Image Credit: Michael Miller, Jimmy Walker)

Antennae galaxies, an intense star-forming region created when two galaxies began to collide some 200 million to 300 million years ago. The bright, blue-white areas show newly formed stars surrounded by clouds of hydrogen, which are colored pink. A similar collision is expected between our galaxy, the Milky Way, and the nearby Andromeda galaxy in several billion years.

Source: national geographic

Credit:NASA/ESA/HUBBLE

Astronauts talking about viewing the earth from the moon, from The Overview Effect: Awe and Self-Transcendent Experience in Space Flight