All posts by Tom

Pushing Asteroids

A rotating asteroid heats up in the sunlight side and as the warmed area rotates into the dark and cold, the stored heat is radiated away. The heat radiated into the cold can cause thrust and push on an asteroid.

The amount of “push” wouldn’t be much, yet over time it can add up and cause the asteroid to change their paths. If you have followed the talk about how to divert a potentially dangerous asteroid you will know variations of this theme has come up.

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A Map of Charon

charonmap

A map of Pluto’s moon (or co-planet depending on your point of view).  Pretty cool when you consider a year ago we only knew Charon as a unassuming dot.   Click the image for a larger view.  If you want a really large view click here.

Here’s the caption released with the map:

The science team of NASA’s New Horizons mission has produced this global map of Pluto’s largest moon, Charon. The map includes all available resolved images of the surface acquired between July 7-14, 2015, at pixel resolutions ranging from 40 kilometers (24 miles) on the anti-Pluto facing hemisphere (left and right sides of the map), to 400 meters (1,250 feet) per pixel on portions of the Pluto-facing hemisphere — the side facing the New Horizons spacecraft when it flew past the dwarf planet — at map center. Many additional images now stored on the spacecraft’s digital data recorders are expected to be transmitted “home” in fall 2015 and these will be used to complete the global map. The map is in simple cylindrical projection, with zero longitude (the Pluto-facing direction) in the center.

The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, designed, built, and operates the New Horizons spacecraft, and manages the mission for NASA’s Science Mission Directorate. The Southwest Research Institute, based in San Antonio, leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama.

Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

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Reddish Arcs on Tethys

redarcTethys

The Cassini spacecraft took these intriguing images. What are those red arcs on Saturns moon Tethys? Keep in mind these are color enhanced and taken through four different filters, including infrared and ultraviolet. Still they are pretty surprising. The press release explains the image and shares a couple of possible explanations. It seems like it could also be a combination of two of the ideas below, ices being contaminated by outgassing.

The press release from the Cassini site:

Unusual arc-shaped, reddish streaks cut across the surface of Saturn’s ice-rich moon Tethys in this enhanced-color mosaic. The red streaks are narrow, curved lines on the moon’s surface, only a few miles (or kilometers) wide but several hundred miles (or kilometers) long. The red streaks are among the most unusual color features on Saturn’s moons to be revealed by Cassini’s cameras.

Continue reading

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It’s a Blue Moon

Tomorrow there will be a Blue Moon. The last one was in August 2012 and the next one is not until January 2018 but the cool thing is the one after that is just a few months later in March 2018.

Those dates are according to one definition. There are two, the second a only a little bit more complicated and arguably the correct version has the next Blue Moon not occurring until May 2016.

Have a look at both definitions. You will note I’m throwing caution to the wind and going with tomorrow.

And YES you CAN have a “blue moon” as you can see in this Science@NASA video:

Video

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Watching Pluto

Seeing Pluto from Earth can be tough enough. Seeing Pluto occulting a distant star and doing it from a plane is exponentially more difficult that takes an amazing amount of planning and skill.

SOFIA or the Stratospheric Observatory for Infrared Astronomy was up to the challenge and successfully observed Pluto with an infrared telescope, here’s how they did it:

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Ceres Elevation Map

colormapceresglobe

From JPL:
The color scale extends 3.7 miles (6 kilometers) below the surface in purple to 3.7 miles (6 kilometers) above the surface in brown. The brightest features (those appearing nearly white) — including the well-known bright spots within a crater in the northern hemisphere — are simply reflective areas, and do not represent elevation.

There is an animated version of the image and links to beautiful wallpaper versions for your computer – at the Dawn website

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

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