Mars | Antares | Saturn | A Triangle

Fellow blogger and sky enthusiast, Scott Levine, pointed out the grouping of two planets and a star in the southern sky in recent nights. Our overcast conditions finally parted and gave us a beautiful view of the grouping the evening of 13 August 2016.

It was about 9 pm local time as we headed home from a gathering of about 30 friends. We have all been to Cuba in the past 3 years and were celebrating with some Cuban foods and drinks. We looked to the south and saw this view exactly as Scott described it. That is the roofline of our house at the bottom right.

Click to embiggen

Click to embiggen

Below is a screen shot of the same part of the sky taken from the software Stellarium. Each planet and some stars are labeled. Since Mars and Saturn are in orbits around the Sun, their positions in the sky change each night. Their arrangement with Antares looks different each night. Watch their progress.

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Jupiter | Harmony of Motion

Galileo used a telescope to cast his eyes upon Jupiter and its moons Io, Europa, Ganymede, and Callisto in 1610. He recorded notebook drawings of their positions nightly. He believed they moved around the planet Jupiter in what appeared to be orbits. His views were but snapshots in time.

Galileo Galilei | Siderius Nuncius | 1610

Telescopes improved over time. Technology brought us better views. Spacecraft Voyager and Galileo gave us marvelous images of the moons. But, those detailed images still gave us only snapshots in time. Those amazing views still lacked the perspective needed to show them in actual orbit about Jupiter.

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Our view of the moons changed with the arrival of the Juno spacecraft on 4 July 2016. It approached Jupiter from above the plane of the orbits of Jupiter and its moons. The perspective allowed the JunoCam camera onboard to image the system multiple times for 17 days between 12 June and 29 June. The still images were made into a movie which shows the four moons in orbit several revolutions around the massive Jupiter.

Notice how the innermost moon Io orbits quickly. The farther moons more slowly. The planets of our solar system behave this way. All bodies in the universe orbit other bodies this same way. We are seeing from a unique perspective above the orbit plane. We are witnessing firsthand the effect of the law of gravitation. It is a thing of beauty. In addition, the three inner moons darken briefly as they pass into the shadow of Jupiter in each orbit.

Quoting Scott Bolton, principal investigator of Juno, Southwest Research Institute:

“This is the king of our solar system, and its disciples going around it. It’s also representative of nature. This is how we look, that’s a mini solar system. And so, I think, to me it’s very significant because we’re finally able to see, with real video, real pictures, this motion. And we’ve only been able to imagine it up until today.”

Stars | How They Change Over Time

Stars go through changes over the course of their existence. The rapidity and violence of those changes depends upon the mass of the star. Low mass stars are slow to change. High mass stars change quickly. Perhaps a case of Live Fast, Die Young.

This post is intended for those readers who have wondered what happens during the lifetime of a star. It is not intended to be an exhaustive description of the life-cycles of stars. Some of the numbers used here represent a range of values assumed for these events. Sources will differ some. There are many parts of star behavior that are complicated and not understood well by the experts. General concepts are presented here to make the processes more understandable.

All stars involve two types of processes that oppose each other. Gravity pulls the star components inward and tries to reduce the star’s volume. Nuclear fusion exerts outward forces and tries to increase the star’s volume. This interplay of opposing forces can create equilibrium. Change in strength of the processes will cause the star to either expand or contract in size. Since the mass of the star is quite constant, the inward pull of gravity is constant. The outward forces can change in strength as nuclear fusion processes change.

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Astro-Images | Pillars of Creation

I’ve created color composites from three grayscale images using the technique in this post. The colors assigned are not necessarily what the human eye would see, but are used to bring out details. Unless otherwise noted, all images used three original grayscales from the Hubble Legacy Archive. Visit the gallery of previous Astro-Images.

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NGC 6611 From ESO

The Eagle Nebula is about 7000 lt yrs distant in the constellation Serpens of the southern skies. The cluster of bright stars at the core was discovered by Jean-Philippe de Chéseaux in 1745-46. Images today show much more detail than Chéseaux was able to see. This image made from 3 greyscale components by the European Southern Observatory in 2009 shows those details. The very bright open cluster of stars barely right of center causes gases to glow and silhouettes of the dust regions. Those bright young stars formed 1-2 million yrs ago.

ESO | European Southern Observatory

 

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Pluto | Close-Up Views of Surface Details

New Horizons spacecraft coasted past Pluto on July 14, 2015. Twenty three minutes before closest approach, the spacecraft scanned the surface in high resolution from the northwest to the southeast limbs of Pluto. It gathered about three dozen sharp images each about 50 miles wide (80 km). Mission scientists have arranged those images into the mosaic below stretching more than 1000 miles long.

© 2016 The Johns Hopkins University Applied Physics Laboratory

 

The mosaic can be easily viewed with this movie. I suggest you watch full-screen more than once. Stop anytime and when new terrain appears highlighted by text at the left. It runs a bit too fast. You can slow down the speed by clicking the gear icon in the lower right after the movie starts.

 

You can also view the full high-resolution jpg image mosaic in higher quality than the movie by using this link. It is several megabytes so be patient if your connection is slow. It is worth it in my opinion.

Keep in mind the highest quality Hubble images of Pluto prior to this mission did not show much. This is a great age of discovery led by teams such as New Horizons.

Astro-Images | Four Nebulae

I’ve created color composites from three grayscale images using the technique in this post. The colors assigned are not necessarily what the human eye would see, but are used to bring out details. Unless otherwise noted, all images used three original grayscales from the Hubble Legacy Archive. Visit the gallery of previous Astro-Images.

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NGC 7009

The Saturn Nebula is in the constellation Aquarius. William Herschel found it 7 Sep 1782 using a telescope in his garden. The image he saw had a central bulge with narrow extensions on either side that made it look a bit like Saturn. Images today show more detail and make it look less like Saturn. The hot central star is emitting jets of debris to the upper left and lower right.

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Saturn Nebula

 

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Mercury Transit | In Case You Missed It

It was 100% cloudy and rainy all day for me. I had to watch online. Here is the complete 7 hrs condensed into about 17 sec. You might need to go full-screen to see Mercury. It is so tiny.

I am so glad to have the online resources available. Go to this SDO site for other video of the transit. Next Mercury transit is 11 Nov 2019.