On August 2, 1971, at the end of the last EVA of the Apollo 15 mission, Commander David Scott took a few minutes to conduct a classical science experiment in front of the TV camera that had been set up just outside the LM Falcon at the Hadley Rille landing site. Scott, a former Air Force pilot, recreated a famous demonstration often attributed to Galileo (which may or may not have actually been performed by the astronomer in Pisa in 1586) that shows how objects of different masses react the same way to gravity when dropped – that is, they fall at the same rate.
By performing the “acceleration test” in the vacuum environment of space (but where there is still an observable downward pull of gravity) the element of air resistance is negated – especially on such a low-mass and low-density object as a falcon feather – thereby creating a more “pristine” setting for the centuries-old experiment than could ever be achieved on Earth.
According to a report on the mission’s science objectives: “During the final minutes of the third extravehicular activity, a short demonstration experiment was conducted. A heavy object (a 1.32-kg aluminum geological hammer) and a light object (a 0.03-kg falcon feather) were released simultaneously from approximately the same height (approximately 1.6 m) and were allowed to fall to the surface. Within the accuracy of the simultaneous release, the objects were observed to undergo the same acceleration and strike the lunar surface simultaneously, which was a result predicted by well-established theory, but a result nonetheless reassuring considering both the number of viewers that witnessed the experiment and the fact that the homeward journey was based critically on the validity of the particular theory being tested. ” (Joe Allen, NASA SP-289, Apollo 15 Preliminary Science Report, Summary of Scientific Results, p. 2-11. Source.)
Launched on July 26, 1971, Apollo 15 was the first of the “J” missions capable of a longer stay time on the moon and greater surface mobility, thanks to the use of the Lunar Roving Vehicle (LRV).Learn more about the Apollo 15 mission here.
Around 600 miles wide, covered in craters and cliffs, a composition of rock and water ice… these are descriptions of both several of Saturn’s moons and the dwarf planet Ceres, based on recent observations by NASA’s Dawn spacecraft. New topographical maps show that, in terms of surface features anyway, Ceres shares similarities with Saturn’s icy satellites.
“The craters we find on Ceres, in terms of their depth and diameter, are very similar to what we see on Dione and Tethys, two icy satellites of Saturn that are about the same size and density as Ceres,” said Paul Schenk, Dawn science team member and a geologist at the Lunar and Planetary Institute (LPI) in Houston, TX. “The features are pretty consistent with an ice-rich crust.”
This newly-released picture of Pluto isn’t quite what our eyes would perceive… but then our eyes aren’t high-tech scientific imaging sensors like the ones aboard New Horizons! An enhanced-color image made from data acquired by the spacecraft’s LORRI and Ralph cameras on July 13, 2015, this view of Pluto shows the many variations in surface compositions across the planet’s visible area. What the compositions are specifically and how they got to be in the places they’re in are questions still being worked on by scientists, so for now we can all just have fun speculating and enjoy the view!
It’s over halfway through 2015 and perhaps it’s high time for an all-new, updated, knock-your-socks-off “blue marble” photo of our beautiful planet Earth. And so earlier this week NASA delivered just that, courtesy of the high-definition EPIC camera (yes, that’s a real acronym) aboard the DSCOVR spacecraft positioned nearly a million miles away toward the Sun. The image above was captured on July 6, 2015, using the camera’s visible-light channels… it’s how Earth would appear to our eyes were we there (with the help of a telephoto lens, that is.)
And it really is a “blue marble” image, of the kind previously only captured by departing (or approaching) planetary exploration spacecraft or from inside Moon-bound Apollo capsules (see below)… you simply can’t get a shot like this from low-Earth orbit!
“This is the first true blue marble photo since 1972.”
– John Grunsfeld, NASA, July 24, 2015
A new image from New Horizons has emerged, showing a new, smaller mountain range on the southwestern border of Pluto’s “heart” region. The image was captured during the July 14 flyby, during which time the spacecraft passed less than 8,000 miles from the planet’s surface.
Everyone knows that Apollo 11 commander Neil A. Armstrong was the first human to set foot on the Moon (and if you didn’t know, that occurred on July 20, 1969 – yes, it really happened). It was a momentous, history-making event that many (like myself) consider one of the most impressive achievements of humankind. But oddly enough, even with high-resolution Hasselblad film cameras there on location, there are very few photos showing Armstrong himself on the surface of the Moon. In fact the one above, a panorama captured by fellow Apollo 11 astronaut Buzz Aldrin, really is the best image in existence of Neil on the Moon.
So…why is that?