Here is your weekly reminder of Psalm 19 — Pluto.
After nearly 10 years and three billion miles, the New Horizons spacecraft has arrived at Pluto. This image was taken by New Horizons yesterday (July 13) before it made its closest approach of about 8,000 miles.
Pluto is perhaps best known in recent times for its demotion from the ninth planet in the solar system to dwarf planet or “plutoid.” It orbits the Sun at about 40 times the Earth’s orbital distance. It is likely the largest and most massive member of the Kuiper Belt, a large collection of icy-rocky objects in the outer region of the solar system.
Pluto imaged by New Horizons. Credit: NASA / JHUAPL / SwRI.
Here is your weekly reminder of Psalm 19 — the Carina Nebula.
The Carina Nebula is a giant diffuse cloud of gas spanning almost 500 light-years and containing many large, bright, hot stars. It’s about three times larger than the great nebula in Orion, but is not as well known, because it’s only visible from the Southern Hemisphere. This is one of my personal favorites, and a portion of it appears in the right-hand menu bar if you scroll down.
This nebula is located on the sky in the constellation Carina (hence its name), and is physically located about 7,000 to 10,000 light-years away in the Carina-Sagittarius spiral arm of the Milky Way Galaxy. For reference, our Solar System is in the adjacent Orion arm. (See below.)
Carina Nebula image credit: ESO/T.
Here is your weekly reminder of Psalm 19 — globular cluster, NGC 7006.
Globular clusters are spherical clusters of stars orbiting in the halos (the outermost regions) of galaxies. This particular cluster is orbiting in the halo of our Milky Way Galaxy, at a distance of about 135,000 light-years from Earth. It appears in the sky in the direction of the constellation Delphinus. Due to its distance, it’s very faint in the sky and therefore difficult to detect with small telescopes. The above image was taken with the Hubble Space Telescope.
The stars in NGC 7006 all formed at about the same time, and are therefore all roughly the same age. They are very old stars — almost as old as the universe — and will remain tightly gravitationally bound to each other their entire lives.
Globular cluster NGC 7006, image credit: HST/NASA.
Here is your weekly reminder of Psalm 19 — the Pleiades.
The Pleiades star cluster. Credit: NASA, ESA, AURA/Caltech, Palomar Observatory.
The Pleiades is an open cluster of stars that forms an asterism — a recognizable pattern of stars — in the sky. The cluster is about 440 light-years from Earth, making it close enough and large enough to be easily observed with the naked eye. It’s also quite lovely through a good pair of binoculars.
The Pleiades is known by many different names, including the Maia Nebula and the Seven Sisters. In Japan, it’s known as Subaru. (You probably recognize the asterism in a certain car company logo now.)
These large, hot stars are relatively young at just 100 million years (our own Sun is 4.5 billion years old), but are already halfway through their main stage of life. The general principle with stars is that the bigger and more luminous the star, the faster it lives.
The cluster is currently passing through a cloud of dusty gas. The light from the stars reflects and scatters off the dust, creating the ethereal glowing wisps surrounding the stars.
Here is your weekly reminder of Psalm 19 — the Needle Galaxy.
This galaxy, also known by its catalog name, NGC 4565, is about as fine an example of an edge-on spiral galaxy as you’ll ever see. If the Milky Way were to be seen at the same distance of 43 million light-years and on its edge, it would look very much like this.
Edge-on spiral galaxy NGC 4565, also known as the Needle Galaxy. Credit: Bruce Hugo and Leslie Gaul/Adam Block/NOAO/AURA/NSF.
The puffy part in the center is the bulge of the galaxy and the extended part is the disk. The dark strip running the length of the galaxy is a dust lane. Dust typically makes up about 10% of the gaseous stuff between the stars in the disk of a spiral galaxy, which doesn’t sound like much, but it’s enough to block a lot of the intense starlight coming from the galaxy.
Here is your weekly reminder of Psalm 19 — the planet Jupiter.
Anyone who has looked up at the night sky is acquainted with Jupiter. It’s the third-brightest object in our sky after the Sun and Venus. It’s also the largest planet in our solar system, a gaseous giant comprised almost entirely of hydrogen and helium. Interestingly, its size, in terms of orders of magnitude, places it exactly in the middle between the Earth and the Sun — it is almost exactly 10 times smaller than our Sun, but just over 10 times larger than the Earth.
An artist’s impression showing Jupiter and its moon Europa using actual Jupiter and Europa images in visible light with ultraviolet images of water vapor plumes superposed on Europa. Credit: NASA, ESA, and M. Kornmesser.
Some call Jupiter a failed star, but that’s an exaggeration. The defining characteristic of a star is that nuclear fusion is occurring in its core; however, Jupiter would need about 80 times more mass for this to occur, so it falls well short of the star limit. Still, it’s pretty massive as planets go, outweighing all of the other planets in our solar system combined by more than a factor of two.
Jupiter is a visual treat for the astronomer for a number of reasons: its colorful bands of clouds, its Galilean moons, and its Great Red Spot. The bands represent regions of rising and descending clouds. The Galilean moons — Callisto, Europa, Ganymede, and Io — were discovered by (you guessed it) Galileo in the 17th century, and are visible through even small amateur telescopes. The Great Red Spot is a turbulent storm that has been raging on Jupiter for hundreds of years. To give you some perspective on size, consider that two Earths could fit inside the Great Red Spot.
The Great Red Spot as seen from Voyager 1. Credit: NASA.
Here is your weekly reminder of Psalm 19–the Helix Nebula, also known as the Eye of God.
The Helix Nebula. Credit: NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner (STScI), and T.A. Rector (NRAO)
This is my favorite nebula. It’s a planetary nebula (PN), so-called because astronomers hundreds of years ago, looking through their not-so-good telescopes, thought these might have been planets. They were wrong, but the name stuck. A PN is actually the cast-off outer layers of a dying low-mass star like our Sun. (High-mass stars die in spectacular light-shows called supernovae.) In the very center of the Helix Nebula you can see the glowing core of the dead star in the process of becoming what’s called a white dwarf.
The Helix Nebula is one of the closest PNs to Earth, and if it were bright enough for you to see it with the naked eye, it would span a distance across the sky almost as big as a full Moon. It looks like a bubble from our vantage point, but that’s a bit of an illusion–we’re really looking at two disks oriented nearly perpendicular to each other.
Astronomers discovered mysterious “cometary knots” appearing to radiate from the center of the nebula in a spoke pattern, and later found these same knots in other PNs. To give you some perspective on the size of the Helix, each knot, excluding the tail, is about the size of our solar system.
“Close-Up of the Helix Nebula” by NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner (STScI), and T.A. Rector (NRAO)
Here is your weekly reminder of Psalm 19—the Pillars of Creation.
The Pillars of Creation. Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
This is arguably NASA’s most famous image, first taken with detail in 1995 by two graduate students at Arizona State University.
The so-called Pillars of Creation are a huge conglomerate of interstellar gas and dust in the Eagle Nebula, some 6,500 light-years from Earth. “Creation” refers to the ongoing formation of stars in the pillars; although NASA has also referred to them as the Pillars of Destruction, since ultraviolet light from the newly-forming stars is gradually boiling off the cool gas in the clouds.
The longest pillar (on the left) is four light-years in height. To give you a sense of scale, that means you could fit over 3,000 solar systems end-to-end in that pillar.
NASA recently commemorated the 25th anniversary of the iconic image by releasing a high-def version (above) earlier this year.
A chance alignment of a planetary nebula — the blown-off outer layers of a dead low-mass star — and a bright star give the illusion of a diamond ring in space:
[Image credit: ESO]
It may look like abstract art, but it’s actually an image of the entire sky in the X-ray part of the spectrum.
The ROSAT All-Sky Survey Map
This image was produced by the ROSAT survey. ROSAT is an X-ray observatory that, like its sister, the Hubble Space Telescope, is in orbit around Earth. The only way to observe celestial X-rays is from extremely high altitudes or in space, since Earth’s atmosphere absorbs them.
The curved blue stripe in the image is the disk of the Milky Way galaxy, and the bright white spots are supernova remnants.