All The Planets In The Solar System Would Fit Between The Earth And The Moon

Jennifer Daniel

Visualization of How Fast a Ball Drops on Various Solar System Bodies

This is an animation of how quickly an object falls 1 km to the surfaces of solar system objects like the Earth, Sun, Ceres, Jupiter, the Moon, and Pluto. For instance, it takes 14.3 seconds to cover that distance on Earth and 13.8 seconds on Saturn.

It might be surprising to see large planets have a pull comparable to smaller ones at the surface, for example Uranus pulls the ball down slower than at Earth! Why? Because the low average density of Uranus puts the surface far away from the majority of the mass. Similarly, Mars is nearly twice the mass of Mercury, but you can see the surface gravity is actually the same… this indicates that Mercury is much denser than Mars.

(via @thekidshouldsee)

The last shuttle

Today NASA released parts of the set of highest-resolution pictures of Pluto from the New Horizons probe’s fly-by in July. As they write, “these latest images form a strip 50 miles (80 kilometers) wide on a world 3 billion miles away.” Imagine that. They are also the highest resolution images we’ll have of Pluto in a long, long time.

This picture, a crop, shows Sputnik Planum and the al-Idrisi mountains, which are made of big chunks of water ice. Be sure to check out the whole thing.

Watch a NASA Spacecraft Touch Down On an Asteroid to Collect a Sample

On Tuesday, NASA’s OSIRIS-REx spacecraft touched down on an asteroid called Bennu for about six seconds in order to collect a mineral sample to bring back to Earth.

The Origins Spectral Interpretation Resource Identification Security - Regolith Explorer spacecraft will travel to a near-Earth asteroid, called Bennu (formerly 1999 RQ36), and bring at least a 2.1-ounce sample back to Earth for study. The mission will help scientists investigate how planets formed and how life began, as well as improve our understanding of asteroids that could impact Earth.

The video above is a time lapse sequence of the touch down, sampling, and subsequent take off.

These images were captured over approximately a five-minute period. The imaging sequence begins at about 82 feet (25 meters) above the surface, and runs through the back-away maneuver, with the last image in the sequence taken at approximately 43 feet (13 meters) in altitude – about 35 seconds after backing away. The sequence was created using 82 SamCam images, with 1.25 seconds between frames.

Space Robot Roll Call

Emily Lakdawalla of the Planetary Society filed a report on humanity’s current roster of spacecraft currently exploring the solar system (and beyond).

Chang'e-4 and Yutu-2 are now past their prime mission and are in their extended mission phases. Their companion SmallSat, Longjiang-2, will crash into the Moon on 31 July to bring its mission to an intentional end. Parker Solar Probe is near aphelion as of 1 July and will reach its third death-defying solar perihelion on 1 September. BepiColombo completed its near-Earth commissioning phase on 5 April and is now settling into its long-cruise phase. Earlier this year, the ESA-JAXA Mercury mission was racing ahead of Earth on an inside track, but its elliptical orbit has now taken it farther from the Sun than Earth, allowing Earth to catch up. It will return to Earth’s neighborhood in April 2020 for a flyby.

I counted roughly 30 different probes and rovers in operation, most of them gathered around the Moon and Mars. Sure, where’s my jetpack and flying car and all that, but the fact that humanity has more than two dozen robots currently exploring the solar system seems pretty futuristic to me.

Wikipedia also has a page listing currently active probes and of course there’s the lovely & informative spaceprob.es as well.

Space cards

There Are Way More Rogue Planets Than We Thought

The galaxy is wild. Our solar system, with its surprising abundance of living creatures and nonstop radiation and asteroid showers, is a placid, private garden compared to the rest of it.

In particular, there are perhaps trillions of rogue planets (planetary bodies ranging from little rocky Earth-sized guys to super-Jupiter gas giants) in the Milky Way, including a surprisingly large fleet of the things right near the galactic core.

This is unusual, since the typical way we detect exoplanets is by marking their repeated procession across a star. But rogue planets, by definition, don’t orbit stars. So the way astronomers find them is a little different, requiring use of gravitational microlensing.

Gizmodo breaks it down:

Data gathered by NASA’s now-retired Kepler Space Telescope has revealed a small population of free-floating planets near the Galactic Bulge. The new finding raises hope that a pair of upcoming missions will result in further detections of unbound planets, which drift through space separated from their home stars….

It’s impossible to know what the conditions are like on these presumed rogue exoplanets, but [astronomer Iain] McDonald said they could be “cold, icy wastelands,” and, if similar in size to Earth, their surfaces would “closely resemble bodies in the outer Solar System, like Pluto.”

The new paper suggests the presence of a large population of Earth-sized rogue planets in the Milky Way. It’s becoming clear that free-floating planets are common. McDonald said his team is currently working to come up with a more precise estimate for how many of them might exist.

Did you catch that part about how McDonald’s team made this discovery using a now-retired telescope? Yeah. Apparently the new telescope projects coming online are both more powerful and (in particular) better equipped to detect gravitational lensing effects, and therefore more likely to detect rogue planets in the future.

The Sweden Solar System

Spanning from comets in the south to the termination shock zone in the northern part of the country, The Sweden Solar System is a scale model of the solar system that spans the entire country of Sweden, the largest such model in the world.

The Sun is represented by the Ericsson Globe in Stockholm, the largest hemispherical building in the world. The inner planets can also be found in Stockholm but the outer planets are situated northward in other cities along the Baltic Sea.