Mergers and Acquisitions

An interacting colossusThis picture shows a galaxy known as NGC 6872 in the constellation of Pavo (The Peacock). Its unusual shape is caused by its interactions with the smaller galaxy called IC 4970 that can be seen just above it. The pair are roughly 300 million light-years away from Earth.

NGC 6872 measures over 500,000 light-years across. It’s the second largest spiral galaxy discovered thus far. Our own galaxy, the Milky Way, measures around 100,000 light-years across.

The upper left spiral arm of NGC 6872 appears distorted and is filled with star-forming regions which appear blue on this Hubble image. That may have been be caused by IC 4970 recently (only about 130 million years ago) passing through this spiral arm. Astronomers have noted that NGC 6872 seems to be relatively sparse in terms of free hydrogen, which is the basis material for new stars. It is probable that if it weren’t for its interactions with IC 4970, NGC 6872 might not have been able to produce these new bursts of star formation.

Image Credit: NASA / ESA

Rubin’s Galaxy

Rubin’s Galaxy (aka UGC 2885) is a giant spiral galaxy about 232 million light-years away. It’s about 800,000 light-years across—roughly 8 times the diameter of the Milky Way. Astronomers estimate it contain a trillion stars, 10 times as many as the Milky Way.

Image Credit: NASA / ESA / B. Holwerda (University of Louisville)

The Earth Seen From Space

One of the most famous images of Earth was taken by Voyager 1 when it was 6 billion km from home. The Earth is a single pixel in that picture called The Pale Blue Dot. Voyager 1 was just about 12,000,000 km above Mt. Everest when it took this picture of the Earth and the Moon on 18 September, 1977. The Moon is on the far side of the Earth in this picture which shows East Asia, the Western Pacific, and part of the Arctic. Mt. Everest in hidden from view on the night side of the Earth.

Image Credit: NASA

Butterfly Nebula

m2d9_hubble_985What happens when a star dies? In the case of low-mass stars like our Sun and M2-9 pictured above, such stars transform themselves into white dwarfs by throwing off their outer gaseous envelopes. The expelled gas often forms a planetary nebula that fades away over thousand of years. M2-9 is a butterfly planetary nebula 2100 light-years away. There are two stars orbiting inside the central gaseous disk 10 times larger than the orbit of Pluto. The expelled gas of the dying star breaks out from the disk in a bipolar pattern.

Image Credit: NASA / ESA

The Case of the Reappearing Supernova

This animation demonstrates how light from Supernova Requiem was split into multiple images by a massive foreground cluster of galaxies along its 10 billion light-year path to Earth. The cluster’s gravity warps the fabric of space which magnified, brightened, and split the supernova’s light into multiple mages detected in 2016 by the Hubble Space Telescope.

However, some of the exploded star’s light is taking a longer path to Earth. It passed through the cluster’s central region where gravity is the strongest. The combination of gravity’s pull, and the longer route across space has delayed the light’s arrival at Earth. That light is predicted to finally reach Earth in 2037.

Stay tuned.

Video Credits: NASA / ESTEC / STScI / Greg T. Bacon (STScI)

A Disorganized Dwarf

A distinctly disorganised dwarfUGC 4459’s diffused and disorganized appearance is characteristic of an irregular dwarf galaxy. Because they lack distinctive structure or shape, irregular dwarf galaxies are typically chaotic in appearance, with neither a nuclear bulge (a tightly-packed central group of stars) nor any trace of spiral arms extending from the center of the galaxy.

Image Credit: NASA

A Brief History of Labor

Mine.

While I was a kid, I earned a bit of spare change mowing lawns, but my first fill-out-this-W2 job was shelving books as a stack assistant in a university library. I was 16, and the “trainee” job paid 70-cents-an-hour. It was indoor work, but required some heavy lifting. One of my stacks contained bound archival copies of newspapers. Bound copies of a week of the New York Times or a month of Pravda are big and heavy. I kept the job through high school.

During the summer between high school and college, I took the examination for a First Class Radio Telephone Operator’s license. I passed the exam, but because of the slow bureaucratic nature of the paperwork, my license did not arrive until after classes had begun in the fall. Because of my family’s support, I didn’t have to work during my freshman year. The following summer, I was offered an on-campus job working as a technician in the Department of Electrical Engineering (my major) for the summer break. During my sophomore year, I picked up occasional odd jobs at businesses that has some sort of technical task that required sign-off by someone with a First Class RTO’s license. That eventually led to my being hired at a local AM station in Nashville. When I went in to pick up my first paycheck, the Program Director heard my voice, and when he found out that had some announcing experience on a campus radio station, he offered me a job.

I spent almost a decade, interrupted by an active duty tour in the Army, working in the broadcast business in Nashville, and the connections made there got me into the music business. Those music business connections got me into pro audio equipment manufacturing jobs in Switzerland, Nashville, and California. Pro audio equipment manufacturing led to the satellite communication industry, which led to work with the flight test community at Edwards AFB. A call from a former Nashville colleague led to a move to the DC area to work on active noise cancellation. And when I decided to get out of management and just sell technical advice, I wound up as a contractor for NASA designing instruments and support systems for both Earth-science and astronomy missions.

Which shows you how things can turn back on themselves. My original interest in science and engineer stems from my fascination with astronomy when I was in elementary school.

I’ve left several gigs on the cutting room floor because they were brief detours from my real career path.

What’s next? I’ve retired twice from working with NASA, but I was asked both times to come back, and I did. I’m 73 and tolerably heathy. I’m still having fun at work. I had been sorta/kinda thinking about retirement around my 75th birthday, but I’m having too much fun still working. I’ll burn that bridge when I get to it.

Messier 96

A galactic maelstromThis is Messier 96, a spiral galaxy a bit more than 35 million light-years away in the constellation of Leo (The Lion). It is roughly the same mass and size as the Milky Way, but unlike our more or less symmetrical galaxy, M96 is lopsided. Its dust and gas are unevenly spread throughout its weak spiral arms, and its core is not exactly at the apparent galactic center. Its arms are also asymmetrical, perhaps because of the gravitational pull of other galaxies within the same group as Messier 96.

Image Credit: ESA / NASA

A White Dwarf and Its Nebula

This is the planetary nebula NGC 3918, a brilliant cloud of colorful gas in the constellation of Centaurus, roughly 4,900 light-years from Earth. In the center of the cloud of gas lies a tiny star, the dying remnant of a red giant. When such a star dies, huge clouds of gas are ejected from its surface before collapses to become a white dwarf. Intense ultraviolet radiation from the tiny remnant star causes the surrounding gas cloud to glow.

NGC 3918 has a distinctive eye-like shape with a bright inner shell of gas and a more diffuse outer shell that extends far from the nebula and looks as if it could be the result of two separate irruptions of gas. However, studies of the object suggest that the two cloud components were formed at the same time but are being blown from the star at different speeds. The powerful jets of gas emerging from the ends of the large structure are estimated to be shooting away from the star at speeds of up to 350,000 km/h/

Image Credit: ESA / NASA

The Cat’s Eye

3000 light-years away from Earth, a dying star is throwing off shells of glowing gas. This picture taken by the Hubble Space Telescope shows that the Cat’s Eye Nebula is one of the most complex planetary nebulae. The Cat’s Eye is so strangely complex that astronomers suspect the bright central object might be a binary star system. Planetary nebula is a term used to describe this general class of objects, but it is somewhat misleading. While these nebulae appear round and planet-like in small telescopes, more powerful instruments reveal them to be stars surrounded by cocoons of gas blown off in the later stages of stellar evolution.

Image Credit: NASA

The Martian Moons

moons_apparent-sizesThe Curiosity rover on Mars used its cameras to take the series of pictures stitched together to make this video. These are the first images from missions on the surface which have caught one moon eclipsing the other. The images were taken on 1 August, 2013, but some of the full-resolution frames were not downlinked until more than a week later, in the data-transmission queue behind higher-priority images being used for planning the rover’s drives.

The picture on the left shows how big the moons of Mars appear to be, as seen from the surface of Mars, compared to the size that Earth’s moon seen from the surface of Earth.

Image and Video Credits: NASA

The Keyhole Nebula

Keyhole_NebulaThe Keyhole is a small dark cloud of cold molecules and dust within the Carina Nebula, containing bright filaments of hot, fluorescing gas that is silhouetted against the much brighter background nebula. The diameter of the Keyhole structure is roughly 7 light years. Its appearance has changed significantly since it was first observed, possibly due to changes in the radiation from Eta Carinae.

Image Credit: NASA