Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 22

NGC 1499: The California Nebula

Image Credit & Copyright: Stephen Kennedy

Explanation: Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud by chance echoes the outline of California on the west coast of the United States. Our own Sun also lies within the Milky Way’s Orion Arm, only about 1,500 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. The California Nebula shines with the telltale reddish glow characteristic of hydrogen atoms recombining with long lost electrons. The electrons have been stripped away, ionized by energetic starlight. Most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot star Xi Persei just to the right of the nebula. A popular target for astrophotographers, this deep image reveals the glowing nebula, obscuring dust, and stars across a 3 degree wide field of view. The California nebula lies toward the constellation Perseus, not far from the Pleiades.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 21

Andromeda in Southern Skies

Image Credit & Copyright: Ian Griffin (Otago Museum)

Explanation: Looking north from southern New Zealand, the Andromeda Galaxy never gets more than about five degrees above the horizon. As spring comes to the southern hemisphere, in late September Andromeda is highest in the sky around midnight though. In a single 30 second exposure this telephoto image tracked the stars to capture the closest large spiral galaxy from Mount John Observatory as it climbed just over the rugged peaks of the south island’s Southern Alps. In the foreground, stars are reflected in the still waters of Lake Alexandrina. Also known as M31, the Andromeda Galaxy is one of the brightest objects in the Messier catalog, usually visible to the unaided eye as a small, faint, fuzzy patch. But this clear, dark sky and long exposure reveal the galaxy’s greater extent in planet Earth’s night, spanning nearly 6 full moons.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 20

Pillars of Creation

Image Credit: Science – NASA, ESA, CSA, STScI, NIRCam
Processing – Joseph DePasquale (STScI), Anton M. Koekemoer (STScI), Alyssa Pagan (STScI)

Explanation: A now famous picture from the Hubble Space Telescope featured these star forming columns of cold gas and dust light-years long inside M16, the Eagle Nebula, dubbed the Pillars of Creation. This James Webb Space Telescope NIRCam image expands Hubble’s exploration of that region in greater detail and depth inside the iconic stellar nursery. Particularly stunning in Webb’s near infrared view is the telltale reddish emission from knots of material undergoing gravitational collapse to form stars within the natal clouds. The Eagle Nebula is some 6,500 light-years distant. The larger bright emission nebula is itself an easy target for binoculars or small telescopes. M16 lies along the plane of our Milky Way galaxy in a nebula rich part of the sky, toward the split constellation Serpens Cauda (the tail of the snake).

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 19

A Galaxy Beyond Stars, Gas, Dust

Image Credit & Copyright: Howard Trottier; Text: Emily Rice

Explanation: Do we dare believe our eyes? When we look at images of space, we often wonder whether they are “real”, and just as often the best answer varies. In this case, the scene appears much as our eyes would see it, because it was obtained using RGB (Red, Green, Blue) filters like the cone cells in our eyes, except collecting light for 19 hours, not a fraction of a second. The featured image was captured over six nights, using a 24-inch diameter telescope in the Sierra Nevada Mountains, in California, USA. The bright spiral galaxy at the center (NGC 7497) looks like it is being grasped by an eerie tendril of a space ghost, and therein lies the trick. The galaxy is actually 59 million light years away, while the nebulosity is MBM 54, less than one thousand light years away, making it one of the nearest cool clouds of gas and dust — galactic cirrus — within our own Milky Way Galaxy. Both are in the constellation of Pegasus, which can be seen high overhead from northern latitudes in the autumn.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 18

Milky Way Auroral Flower

Image Credit & Copyright: Göran Strand

Explanation: Could the stem of our Milky Way bloom into an auroral flower? No, not really, even though it may appear that way in today’s featured all-sky image. On the left, the central plane of our home galaxy extends from the horizon past the middle of the sky. On the right, an auroral oval also extends from the sky’s center — but is dominated by bright green-glowing oxygen. The two are not physically connected, because the aurora is relatively nearby, with the higher red parts occurring in Earth’s atmosphere only about 1000 kilometers high. In contrast, an average distance to the stars and nebulas we see in the Milky Way more like 1000 light-years away – 10 trillion times further. The featured image composite was taken in early October across a small lake in Abisko, northern Sweden. As our Sun’s magnetic field evolves into the active part of its 11-year cycle, auroras near both of Earth’s poles are sure to become more frequent.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 13

Dust Shells around WR 140 from Webb

Image Credit: NASA, ESA, CSA, JWST, MIRI, ERS Program 1349; Processing: Judy Schmidt

Explanation: What are those strange rings? Rich in dust, the rings are likely 3D shells — but how they were created remains a topic of research. Where they were created is well known: in a binary star system that lies about 6,000 light years away toward the constellation of the Swan (Cygnus) — a system dominated by the Wolf-Rayet star WR 140. Wolf-Rayet stars are massive, bright, and known for their tumultuous winds. They are also known for creating and dispersing heavy elements such as carbon which is a building block of interstellar dust. The other star in the binary is also bright and massive — but not as active. The two great stars joust in an oblong orbit as they approach each other about every eight years. When at closest approach, the X-ray emission from the system increases, as, apparently, does the dust expelled into space — creating another shell. The featured infrared image by the new Webb Space Telescope resolves greater details and more dust shells than ever before.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 12

Ou4: The Giant Squid Nebula

Image Credit & Copyright: Tommy Lease

Explanation: A mysterious squid-like cosmic cloud, this nebula is very faint, but also very large in planet Earth’s sky. In the image, composed with 30 hours of narrowband image data, it spans nearly three full moons toward the royal constellation Cepheus. Discovered in 2011 by French astro-imager Nicolas Outters, the Squid Nebula’s bipolar shape is distinguished here by the telltale blue-green emission from doubly ionized oxygen atoms. Though apparently surrounded by the reddish hydrogen emission region Sh2-129, the true distance and nature of the Squid Nebula have been difficult to determine. Still, a more recent investigation suggests Ou4 really does lie within Sh2-129 some 2,300 light-years away. Consistent with that scenario, the cosmic squid would represent a spectacular outflow of material driven by a triple system of hot, massive stars, cataloged as HR8119, seen near the center of the nebula. If so, this truly giant squid nebula would physically be over 50 light-years across.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 11

Stars, Dust, Pillars, and Jets in the Pelican Nebula

Image Credit & Copyright: Adriano Almeida

Explanation: What dark structures arise within the Pelican Nebula? On the whole, the nebula appears like a bird (a pelican) and is seen toward the constellation of a different bird: Cygnus, a Swan. But inside, the Pelican Nebula is a place lit up by new stars and befouled by dark dust. Smoke-sized dust grains start as simple carbon compounds formed in the cool atmospheres of young stars but are dispersed by stellar winds and explosions. Two impressive Herbig-Haro jets are seen emitted by the star HH 555 on the right, and these jets are helping to destroy the light year-long dust pillar that contains it. Other pillars and jets are also visible. The featured image was scientifically-colored to emphasize light emitted by small amounts of heavy elements in a nebula made predominantly of the light elements hydrogen and helium. The Pelican Nebula (IC 5067 and IC 5070) is about 2,000 light-years away and can be found with a small telescope to the northeast of the bright star Deneb.

 

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