Category Archives: Dwarf Planets
The dwarf planet Ceres, at 587 miles wide the largest object in the main asteroid belt between Mars and Jupiter, has a different surface composition than previously thought—and it took NASA and DLR’s Boeing 747-based SOFIA observatory to make the distinction. By observing Ceres in mid-infrared, only possible from high altitudes above infrared-absorbing water vapor, SOFIA found that Ceres is covered in silicates—pyroxenes—that likely came from impacts, the result of infalling material from elsewhere in the asteroid belt…the “dust” of asteroid collisions.
They’re here and they’re from outer space! The U.S. Postal Service has two new sets of Forever® stamps based on NASA’s exploration of the Solar System: the Views of Our Planets and Pluto—Explored! series, both of which become available for purchase on May 31, 2016.
Designed by Antonio Alcalá, the Views of Our Planets stamps feature eight images of the major planets in the Solar System, as seen by various spacecraft over the past three decades. Pluto—Explored! highlights an extended-color image of the distant dwarf planet and a rendering of the New Horizons spacecraft, which gave us our first good look at Pluto in July 2015.
The last stamp to feature Pluto was a 29-cent version issued in 1991, which showed a featureless tan orb with the words “not yet explored” beneath it… we can now officially call that version obsolete!
Both sets are Forever stamps, which means they are always good as first-class postage for 1 oz. envelopes, whatever the current postage price may be. You can purchase
both in collectible sheets at your local U.S. Post Office or online here.
*Note: the Pluto stamps are only available online.
Ceres’ Haulani Crater, with a diameter of 21 miles (34 km), shows evidence of landslides from its crater rim. Smooth material and a central ridge stand out on its floor. This image was made using data from NASA’s Dawn spacecraft when it was in its high-altitude mapping orbit, at a distance of 915 miles (1,470 km) from Ceres.
This enhanced color view allows scientists to gain insight into materials and how they relate to surface morphology. Rays of bluish ejected material are prominent in this image, the color having been associated with young features.
Turns out there is something new under the Sun, at least to us; on Tuesday, April 26 scientists announced the discovery of a new moon in the Solar System—but it’s not around Earth, or Jupiter, or Saturn, or any of the planets that you’ve long been familiar with. This new moon is orbiting a distant world even farther away and smaller than Pluto: the dwarf planet Makemake (pronounced mah-kay mah-kay), located deep in the Kuiper Belt and currently over 52 times farther away from the Sun than we are.
After more than a dozen years of head-scratching we finally have our first really good look at the weird bright spot on Ceres, thanks to NASA’s Dawn spacecraft and its low-altitude mapping orbit (aka LAMO) around the dwarf planet. Appearing from 240 miles up as a dome covered in cracks and rising from the surrounding darker terrain, the largest of Ceres’ bright spots looks not unlike… a giant pimple.
Researchers using the High Accuracy Radial velocity Planet Searcher (HARPS) instrument on ESO’s 3.6-meter telescope at La Silla have detected “unexpected” changes in the brightness of Ceres during observations made in July and August of 2015. Variations in line with Ceres’ 9-hour rotational period were expected, but other fluctuations in brightness were also found that indicate albedo changes on a daily, diurnal basis.
Long story short: Ceres is slowly “blinking.”