Pluto | What Have We Learned?

Top findings by scientists with the New Horizons Pluto Mission were published in March 2016 in the journal Science. A list of the highlights is available in this news release from NASA. I will attempt to summarize each finding and their significance.

Images used in this post are from Johns Hopkins Applied Physics Laboratory. Click on any for a much larger and impressively detailed view. Their entire collection of released images is available here for your browsing pleasure. I encourage you to look through the images. Our views of Pluto went from a tiny mottled orb a year ago to ones with great detail and mystery. Each of the 120+ images includes an explanation of the important details.

Now on to the top findings…

1. Geologically active

The ages of solar system bodies can be estimated by counting the number of craters. This method tells us Pluto is about 4 billion years old, a little younger than Earth. The heart-shaped light colored, icy region called Sputnik Planum is devoid of cratering. That indicates it is young no more than 10 million years. Sputnik Planum is smooth and about the size of Texas.

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Dawn | Views From LAMO

The Dawn spacecraft is in low altitude mapping orbit (LAMO) around the dwarf planet Ceres at an altitude of 240 mi (385 km), closer than the Space Station orbits Earth. Amazing detail is being imaged and analyzed. Some of those features are highlighted in this brief Jet Propulsion Lab video. Visit this link for previous posts about Dawn.

 

A recent enhanced image in color of Occator crater. Click to embiggen for greatest detail.

Space Station Transit of the Sun

8 May 2009 Transit

With a solar filter over the lens, I aimed my video camera at the Sun and zoomed to get a full screen view. The tripod mount held it steady. The transit took only 2 seconds. I let the camera record for several minutes, then rushed home to see if the ISS was visible on the recording. This video is slowed down to make it easier to follow. Else, you might blink and miss it.

 

How Did I Know It Would Transit?

Each week, I get an email notice about upcoming events such as ISS passes over my location. I can go out in fair weather and watch it go over. It is as bright as Venus and moves fast. Every few months, the Sun or Moon is positioned so the ISS passes across their face as viewed from my location. The email alert tells me where and when to be positioned so my view has the ISS pass across the center of the face. I got one of those alert emails a few days ago.

This map shows a centerline of the ISS in front of the Sun for the morning of 27 Feb 2016 at about 7:38m59s am CST. It plots every 0.5s. I live quite close to the line and positioned myself where it crosses 380.

ISS_SunTran

 

27 Feb 2016 Result

I planned to test a new set of equipment for recording the event. According to the email alert, the small silhouette of the ISS would pass from right to left across the center of the solar disk. I let the camera record long enough to capture the transit and then hurried home to check the results. You can judge for yourself in the video below. It has been shortened in order to show the transit.

 

Either I completely missed capturing the ISS and got a gull transit instead. Or, the ISS has been fitted with a pair of flapping wing solar panels. That seems very unlikely. I hope to have better luck next time.

 

6 Sep 2015 Transit

Here is a high quality video of a transit as seen 6 Sep 2015 from Shenandoah National Park, Front Royal, VA.  Credit to NASA/Bill Ingalls.

ISS Solar Transit (NHQ201509060002 - animated)

Gravity Waves | Both LIGO Record Them

A little more than 1.3 billion years before 14 Sep 2015, a pair of 29 and 36 solar mass black holes orbited each other, slowly getting closer together. On that date, they merged into one black hole of 62 solar masses. Their merger radiated 3 solar masses of energy in a fraction of a second.

This animation from Simulating Extreme Spacetime SXS uses calculated effects from the equations of Einstein to simulate the view of the star field behind the black holes. Imagine you are close enough to watch their dance. Paths of starlight are altered by the masses of the black holes. It is also greatly slowed down. The black holes were actually moving a high fraction of the speed of light as they orbited just before merger.

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Dawn | Flyover Dwarf Planet Ceres

The spacecraft Dawn is orbiting dwarf planet Ceres in the Low Altitude Mapping Orbit LAMO of about 240 miles (385 km). From August to October 2015, Dawn was in the High Altitude Mapping Orbit HAMO of 900 miles (1450 km). Images from that orbit captured many interesting features of Ceres. The German Aerospace Center DLR compiled many of these images into a simulated flyover of them. Expect another flyover video at a later date using images from the much closer LAMO.


Several previous posts about the Dawn mission are available at this link.

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Dawn | In Final Mapping Orbit

SoccerBallImagine a soccer ball held 3.5″ (9 cm) from your eyes. That is the scale of how close the spacecraft Dawn is to the surface of Ceres in polar orbit of 5.4 hrs. Actual altitude is about 240 mi (385 km), as close as the International Space Station is to Earth. Dawn will remain in this low altitude mapping orbit (LAMO) forever. It does not have enough fuel to move to another orbit or location in space. The primary mission will end in mid-2016. The mission might be extended if science, resources, and money warrant.

The orbit diagram below shows the path of Dawn the final three months of 2015. In October, the spacecraft was 915 mi (1470 km) from Ceres traveling 400 mph (645 km/h) shown as an outer green ring. This orbit was called the high altitude mapping orbit (HAMO). Upon completion of scientific duties, the ion propulsion engine was turned on. That weak thrust caused Dawn to spiral inward toward Ceres. The blue lines in the diagram show the spiral path.

Image Mapping

After nearly 7 weeks of ion engine thrusting, Dawn reached the LAMO shown as the inner green ring. Because it fell deeper into the gravity field of Ceres, it gained speed. Dawn is now going 610 mph (980 km/h). Images are returned daily and are available to browse at this fine link. Bookmark and return often.

DawnLAMO

NASA | JPL-Caltech

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