Category: Numbers

Glowing Waves Make 4

Credit: ESA/Hubble and NASA

Glowing waves of material ejected from a dying star trace out the number four in this image of IC 4634 from NASA’s Hubble Space Telescope.

IC 4634The end of a star’s life is anything but peaceful. Once the fuel source of hydrogen and helium run out for a star like our Sun, it swells to enormous size and becomes a red giant. During this process, the star puffs off bubbles of gas and becomes a planetary nebula. If the star is spinning, as seen with IC 4634, symmetrical rings of material are thrown off. Far away from the star, S-shaped bars of material were flung off first. More recently, material was cast away as well as a donut-shaped bubble of gas. All that is left behind is the hot-white core of the dying star called a white dwarf. The intense ultraviolet light from this core causes the gas in the nebula to glow.

IC 4634 is located about 7,500 light-years away toward the constellation Ophiuchus, the Serpent Holder. Planetary nebulae have nothing to do with planets. Astronomers searching for planets in the 18th and 19th centuries encountered many objects in the sky that had faint rounded disks similar to the distant planets of Uranus and Neptune.

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Galactic 3

Credit: NASA and The Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)

Huge tidal tails of stars and gas form a galactic “three” in this image of ESO 148-2 from NASA’s Hubble Space Telescope.

ESO 148-2Explore the image of the interacting pair of galaxies that make up ESO 148-2. The bright cores of the galaxies, in the center of the image, contain a large number of stars embedded in thick clouds of dust. Both galaxies used to be disc-shaped spiral galaxies. Gravity interactions over a long period of time have brought them to the brink of merging completely. Follow the arcs of the tidal tails forming the top and bottom traces of the number three. New blue stars are seen forming in these stretched out areas of gas and dust. When these nebulae get pushed and pulled by gravity, dense areas form and can collapse under their own gravity and can form new stars.

ESO 148-2 is one of the most luminous galaxies in the universe when viewed with infrared telescopes. The interacting galaxy is almost 600 million light-years from Earth toward the southern constellation Tucana. A light-year is the distance light travels in one Earth year; about 6 trillion miles. When the ancient light left ESO 148-2 600 million years ago, only soft-bodied animals such as sponges and worms lived in Earth’s oceans. No plants or animals lived on land.

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Spirally Number 2

Credit: NASA and The Hubble Heritage Team (STScI/AURA)

Glowing gas and starlight with dark bands of interstellar dust create a cosmic number two in this image from NASA’s Hubble Space Telescope. NGC 1300 is considered the typical barred spiral galaxy.

NGC 1300Explore the image of NGC 1300. In a barred spiral, the galaxy arms connect to the ends of a bar of stars that contains the galactic nucleus. Some astronomers believe that the Milky Way Galaxy may be a barred spiral. Check out the newest and hottest stars in the sweeping spiral arms. Dense dust lanes trace out structures within the spiral arms and bar. The bright blue areas at the outside of these spiral arms are actually giant star clusters. In the central bar, older cooler stars reside. Zoom in to the galaxy’s core. The nucleus of NGC 1300 shows what astronomers call a “grand-design” spiral structure. Astronomers see this structure in the largest barred spiral galaxies. Flit from your choice of hundreds of background galaxies. These far-off galaxies are visible even through the densest part of the spiral arms.

NGC 1300 is located about 69 million light-years from Earth toward the constellation Eridanus. The meandering constellation Eridanus represents the Po River in ancient mythology and is the source of waters flowing from Aquarius, the water bearer.

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Number 1 – NGC 5866

Credit: NASA and The Hubble Heritage Team (STScI/AURA)

Today’s image is brought to you by the number one. NGC 5866 is an edge-on galaxy to Earth spectacularly captured in this image from NASA‘s Hubble Space Telescope.

NGC 5866Explore the dark dust lane along the edge of NGC 5866, also known as the Spindle Galaxy. For a lenticular galaxy, this dust lane is unusual. Lenticular galaxies get their names from the lens-like shape of their galactic disks; bulging core and thin disk. Usually dust lanes in these kinds of galaxies are found concentrated the the nucleus. Moving out from the center of the galaxy, young, blue stars can be seen in the galaxies’ disk. And in the background, hundreds of background galaxies can be seen.

NGC 5866 is found in the northern constellation Draco, the dragon, about 44 million light-years from Earth; not that far in the cosmic scheme of things. Light, traveling at about 6 trillion miles per year, would take about 60,000 years to cross the face of NGC 5866. This makes it about half the size of our Milky Way Galaxy. But the galaxy still contains millions of stars. The galaxy was probably discovered by astronomers Pierre Méchain or Charles Messier in 1781. The galaxy may be M102 in Messier’s catalog. M102 was misnamed and several historians have found different objects matching the name. British astronomer William Herschel independently found the galaxy in 1788.

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Number Zero

Credit: NASA and The Hubble Heritage Team (STScI/AURA)

We’re starting a new series here at Starry Critters; numbers and letters. Today’s image is brought to you by the number zero.

Hot, blue stars form a halo around the yellow center of a galaxy known as Hoag’s Object. From Earth it appears as the huge number zero as we view this odd galaxy face-on in this image from NASA‘s Hubble Space Telescope.

The ring of young, massive stars stretches about 120,000 light-years across; slightly larger than our Milky Way Galaxy. The ring may be the result of new star formation caused when one galaxy zoomed through the other. Scientists don’t see a second galaxy that could be responsible. Another idea is that the ring is the shredded remains of a galaxy that encountered the older yellow galaxy in the center. Astronomers believe this encounter took place two to three billion years ago.

Explore the the billions of stars that make up this galaxy. The halo consists of blue stars grouped together in giant clusters. They are recently born out of huge clouds of gas and dust. These massive, new stars won’t live long. Within a couple million years they will start to explode in supernova brighter than the entire galaxy. The gap in the center may not be entirely empty. Faint star clusters or individual stars may be sprinkled lightly in this area. Can you pick out distant spiral galaxies and another ring galaxy shining through this area?

Light from Hoag’s Object has traveled a long time to reach Earth, taking nearly 600 million light-years to reach us. This unusual ring galaxy is found in the constellation Serpens, the Serpent. It is named after Arthur Allen Hoag who discovered it in 1950. Hoag believed it to be either a planetary nebula or a peculiar galaxy.


The ancient peoples saw pictures in the sky. From those patterns in the heavens, ancient storytellers created legends about heroes, maidens, dragons, bears, centaurs, dogs and mythical creatures...
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