Another Lonely Galaxy

ngc-4414NGC 4414 is an unbarred spiral galaxy about 62 million light-years away in the constellation Coma Berenices. It has short segments of spiral structure but lacks the dramatic well-defined spiral arms of a grand design spiral galaxy. It’s also a very isolated galaxy without signs of past interactions with other galaxies.

Image Credit: NASA / ESA

A Binary Asteroid

This time-lapse video was put together from Hubble Space Telescope photos. It shows two asteroids with comet-like features orbiting each other. The asteroid pair, called 2006 VW139/288P, was observed in 2016, just before its closest approach to the Sun. The photos reveal the binary system has a tail like a comet. The apparent movement of the tail is caused by changes in the relative alignment between the Sun, Earth, and 2006 VW139/288P between observations. The tail orientation is also affected by a change in the particle size. The pair was emitting relatively large particles (about 1 mm) in late July, and the tail was pointing in more or less the same direction as most of the particle emissions. However, after 20 September, 2016, the tail began to point in the opposite direction as pressure of sunlight pushed smaller (about 10 µm) dust particles away from the Sun.

Credits: NASA, ESA, and J. DePasquale and Z. Levay (STScI)

The Heart of the Crab

Here’s NASA’s description of this video—

This video starts with a composite image of the Crab Nebula, a supernova remnant that was assembled by combining data from five telescopes spanning nearly the entire breadth of the electromagnetic spectrum: the Very Large Array, the Spitzer Space Telescope, the Hubble Space Telescope, the XMM-Newton Observatory, and the Chandra X-ray Observatory.

The video dissolves to the red-colored radio-light view that shows how a neutron star’s fierce “wind” of charged particles from the central neutron star energized the nebula, causing it to emit the radio waves. The yellow-colored infrared image includes the glow of dust particles absorbing ultraviolet and visible light. The green-colored Hubble visible-light image offers a very sharp view of hot filamentary structures that permeate this nebula. The blue-colored ultraviolet image and the purple-colored X-ray image shows the effect of an energetic cloud of electrons driven by a rapidly rotating neutron star at the center of the nebula.

Video Credit: NASA, ESA, J. DePasquale (STScI)

NGC 3370

IDL TIFF fileSpiral galaxy NGC 3370 is roughly the same size and general layout as our Milky Way. It’s about 100 million light-years away in the direction of the constellation Leo. It dominates the foreground of this Hubble image (click it to embiggen) which shows other galaxies scattered in the background. This particular picture is detailed enough for study of individual pulsating stars known as Cepheid variables that can be used to accurately determine the distance to the galaxy. NGC 3370 is also home to a recent type Ia supernova. Combining the known distance to this “standard candle” supernova and the Cepheid data with observations of other supernovae at even greater distances has been useful in refining estimates of the age and expansion rate of the Universe.

Image Credit: NASA

A Star Is Born

Actually, a whole lot of them. This massive, young stellar grouping, called R136, is only a few million years old and resides in the 30 Doradus (aka Tarantula) Nebula, a turbulent star-birthing region in the Large Magellanic Cloud, a satellite galaxy of our Milky Way. There is no known star-forming region in our galaxy as large or as prolific as 30 Doradus.

Many of the diamond-like icy blue stars are among the most massive stars known. Some are 100 times more massive than our sun. These huge stars are destined to explode like a string of firecrackers when they become supernovas in a few million years.

This picture, taken in ultraviolet, visible, and red light by Hubble’s Wide Field Camera 3, spans about 100 light-years. The nebula is close enough to Earth that Hubble can resolve individual stars, giving astronomers important information about the stars’ birth and evolution.

The brilliant stars are carving deep cavities in the surrounding material by unleashing a torrent of ultraviolet light, and strong stellar winds (streams of charged particles), which scour away the enveloping hydrogen gas cloud in which the stars were born. The image shows a  what looks like a landscape of pillars, ridges, and valleys, as well as a dark region in the center that looks a bit like the outline of a Christmas tree. In addition to sculpting the gaseous “terrain,” these brilliant stars are also helping create a new generation of offspring. When the stellar winds hit dense walls of gas, they create shock waves which can create a new wave of star birth.

This picture was put together from observations taken in October, 2009. The blue color is light from the hottest, most massive stars; the green from the glow of oxygen; the red from fluorescing hydrogen.

Image Credit: NASA

Warp Factor

How did spiral galaxy ESO 510-13 get bent out of shape? The disks of many spiral galaxies are thin and flat, but with the gaps between star they are not solid. Spiral disks are loose conglomerations of billions of stars and diffuse gas all gravitationally orbiting a galaxy center. The common flat disk shape  is thought to be created by sticky collisions of large gas clouds early in the galaxy’s formation. Warped disks are not uncommon, though, and even our own Milky Way Galaxy is thought to have a bit of warp. The causes of spiral warps are still being investigated, but some warps are thought to result from interactions or even collisions between galaxies. ESO 510-13, shown in the digitally sharpened Hubble image above, is about 150 million light years away and about 100,000 light years across.

Image Credit: NASA

Eagle Nebula

ESA’s Herschel Space Observatory captured the image above of the Eagle nebula with its intensely cold gas and dust. The Pillars of Creation are seen inside the circle and at left in a famous picture made by NASA’s Hubble Space Telescope in 1995.

The Herschel image of the Eagle nebula shows the self-emissions of the intensely cold nebula’s gas and dust as never seen before. Each color shows a different temperature of dust, from around 10 degrees above absolute zero (10 K or -442 °F) for the red, up to around 40 K (or -388 °F) for the blue.

Herschel reveals the intricate nature of the nebula’s tendrils of gas and dust, with large gaps forming a cave-like surrounding to the famous pillars. The gas and dust provide the material for the star formation that is still under way inside this enigmatic nebula.

Image Credits: Herschel, ESA. Hubble, NASA

The Solar System (c. AD 5,000,000,000)

Over 2,000 light-years away, the Little Ghost Nebula offers a glimpse of the fate of our Sun, which could produce its own planetary nebula only about 5 billion years from now.  Round and planet-shaped, the nebula (AKA, NGC 6369) is also relatively faint—thus the nickname Little Ghost Nebula. Planetary nebulae really have nothing to do with planets. They are created at the end of a sun-like star’s life as its outer layers expand into space while the star’s core shrinks to become a white dwarf. The transformed white dwarf star in the middle of the nebula radiates strongly at ultraviolet wavelengths and powers the expanding nebula’s glow. This nebula’s main ring structure is about a light-year across and the glow from ionized oxygen, hydrogen, and nitrogen atoms are colored blue, green, and red respectively.

Image Credit: NASA/Hubble Heritage Team


This is the Crab Nebular, the sort of mess that is left when a star explodes. The Crab Nebula, the result of a supernova seen in 1054 AD, spans about 10 light-years. In the nebula’s very center lies a pulsar:  a neutron star roughly as massive as the Sun but with only a few kilometers in diameter. The Crab Pulsar rotates about 30 times each second.

This image was taken by the Hubble Space Telescope. It’s also know as M1, the first nebula in the Messier catalog.

Image Credit: NASA

Hello, Dave!

Hello, Dave! What’s large and blue and can wrap itself around an entire galaxy?

A gravitational lens mirage.

In this Hubble Space Telescope picture the gravity of a luminous red galaxy has gravitationally distorted the light from a much more distant blue galaxy. Such light bending usually results in two discernible images of the distant galaxy, but here the lens alignment is so precise that the background galaxy is distorted into a horseshoe, almost a complete ring. Since such a lensing effect was generally predicted in some detail by Albert Einstein over 70 years ago, rings like this are now known as Einstein Rings.  Strong gravitational lenses like this are more than oddities—their multiple properties allow astronomers to determine the mass and dark matter content of the foreground galaxy lenses.

I think it’s quite lovely. Don’t you, Dave?

Image Credit: NASA, ESA/Hubble

Cosmic Exclamation Point!

VV 340 is a group of two galaxies on a collision path about 450 million light years from Earth. The edge-on galaxy near the top of the image is VV 340 North and the face-on galaxy at the bottom of the image is VV 340 South. In a few millions of years these two spirals will merge—just as our galaxy, the Milky Way, and  our neighbor Andromeda will likely meet billions of years from now. This false color image was derived using data from NASA’s Chandra X-ray Observatory (purple) along with optical data from the Hubble Space Telescope (red, green, blue).

Image Credit: NASA

Light Echo

Back when I was in the music business in Nashville, “light echo” meant less reverb on a track. A “light echo”in astronomy means light from the flash of a nova or supernova being reflected by successively more distant rings in the ambient interstellar dust that surrounded the star before it exploded. In 2002, the star V838 Mon’s outer surface suddenly greatly expanded. It became the brightest star in the entire Milky Way Galaxy. Then, just as suddenly, it faded. Novae and supernovae throw matter out into space, but while the V838 Mon flash appears to expel material, what is seen here is actually an outwardly moving light echo of the bright flash. The Hubble Space Telescope took this image in early 2004 when the light echo was roughly 6 light-years across.

Image Credit: NASA/ESA/STScI

Giant Butterfly

Few butterflies have a wingspan so vast. This dramatic close-up of the Butterfly Nebula NGC 6302, a dying star’s nebula, was taken by the Hubble Space Telescope.  With an estimated surface temperature of about 250,000 degrees C, the central star is exceptionally hot though—shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust. Cutting across a bright cavity of ionized gas, the dust torus surrounding the central star is near the center of this view, almost edge-on to the line-of-sight. NGC 6302 is 4,000 light-years away in the constellation Scorpius.