Charon, Moon Of Pluto, Observed By NASA’s New Horizons Probe On This Day In 2015.

Just storm in a Canada

September 15

This one is technically not yet history, because at the time of posting, the little craft has about half an hour left to go.  That said, let’s proceed.

In 2017, NASA’s Cassini space probe ended its twenty-year mission at Saturn.  After a nearly-seven-year-long journey there, it orbited the ringed planet for 13 years and just over two months, gathering copious amounts of information about the planet, said rings, and many of its moons.  It landed an ESA probe called Huygens on Titan, the first-ever soft landing in the outer Solar System.  It discovered lakes, seas, and rivers of methane on Titan, geysers of water erupting from Enceladus (and passed within 50 miles of that moon’s surface), and found gigantic, raging hurricanes at both of Saturn’s poles.  

And the images it returned are beautiful enough to make you weep.

On this day in 2017, with the fuel for Cassini’s directional thrusters running low, the probe was de-orbited into the Saturnian atmosphere to prevent any possibility of any contamination of possible biotic environments on Titan or Enceladus.  The remaining thruster fuel was used to keep the radio dish pointed towards Earth so the probe could transmit information about the upper atmosphere of Saturn while it was burning up due to atmospheric friction.

This is us at our best.  We spent no small amount of money on a nuclear-powered robot, launched it into space, sent it a billion miles away, and worked with it for two decades just to learn about another planet.  And when the repeatedly-extended missions were through, we made the little craft sacrifice itself like a samurai, performing its duty as long as it could while it became a shooting star in the Saturnian sky.

Rhea occulting Saturn

Water geysers on Enceladus

Strange Iapetus

Look at this gorgeousness

A gigantic motherfucking storm in Saturn’s northern hemisphere

Tethys

This image is from the surface of a moon of a planet at least 746 million miles away.  Sweet lord

Mimas

Vertical structures in the rings.  Holy shit

Titan and Dione occulting Saturn, rings visible

Little Daphnis making gravitational ripples in the rings

That’s here.  That’s home.  That’s all of us that ever lived.

Saturn, backlit

A polar vortex on the gas giant

Icy Enceladus

(All images from NASA/JPL)

The Moon with the ISS transitioning in front of it.  Amazing view considering the ISS moves over and past it in a matter of seconds.

Storm Clouds of Jupiter

Discovery Shuttle docked to the ISS. 🌎🚀

Mars Helicopter: 6 Things to Know About Ingenuity

When our Perseverance Mars rover lands on the Red Planet on Feb. 18, 2021, it will bring along the Ingenuity helicopter.

This small-but-mighty craft is a technology demonstration that will attempt the first powered, controlled flight on another planet. Its fuselage is about the size of a tissue box, and it weighs about 4 pounds (1.8 kg) on Earth. It started out six years ago as an implausible prospect and has now passed its Earthbound tests.

Here are six things to know about Ingenuity as it nears Mars:

1. Ingenuity is an experimental flight test.

This Mars helicopter is known as a technology demonstration, which is a project that aims to test a new capability for the first time with a limited scope. Previous technology demonstrations include Sojourner, the first Mars rover, and the Mars Cube One (MarCO) CubeStats that flew by Mars.

Ingenuity does not carry any science instruments and is not part of Perseverance’s science mission. The only objective for this helicopter is an engineering one – to demonstrate rotorcraft flight in the thin and challenging Martian atmosphere.

2. Mars won’t make it easy for Ingenuity.

Mars’ atmosphere is around 1% the density of Earth’s. Because of that lack of density, Ingenuity has rotor blades that are much larger and spin faster than a helicopter of Ingenuity’s mass here on our planet. It also must be extremely light to travel to Mars.

The Red Planet also has incredibly cold temperatures, with nights reaching minus 130 degrees Fahrenheit (-90 degrees Celsius) in Jezero Crater, where our rover and helicopter will land. Tests on Earth at the predicted temperatures indicate Ingenuity’s parts should work as designed, but the real test will be on Mars.

3. Ingenuity relies on Perseverance for safe passage to Mars and operations on the Martian surface.

Ingenuity is nestled sideways under Perseverance’s belly with a cover to protect the helicopter from debris during landing. The power system on the Mars 2020 spacecraft periodically charges Ingenuity’s batteries during the journey to the Red Planet.

In the first few months after landing, Perseverance will find a safe place for Ingenuity. Our rover will shed the landing cover, rotate the helicopter so its legs face the ground and gently drop it on the Martian surface.

4. Ingenuity is smart for a small robot.

NASA’s Jet Propulsion Laboratory will not be able to control the helicopter with a joystick due to delays communicating with spacecraft across interplanetary distances. That means Ingenuity will make some of its own decisions based on parameters set by its engineering team on Earth.

During flight, Ingenuity will analyze sensor data and images of the terrain to ensure it stays on a flight path designed by project engineers.

5. The Ingenuity team counts success one step at a time.

Ingenuity’s team has a long list of milestones the helicopter must pass before it can take off and land in the Martian atmosphere.

Surviving the journey to and landing on Mars

Safely deploying onto the Martian surface from Perseverance’s belly

Autonomously keeping warm through those intensely cold Martian nights

Autonomously charging itself with its solar panel

Successfully communicating to and from the helicopter via the Mars Helicopter Base Station on Perseverance

6. If Ingenuity succeeds, future Mars exploration could include an ambitious aerial dimension.

The Mars helicopter intends to demonstrate technologies and first-of-its-kind operations needed for flying on Mars. If successful, these technologies and flight experience on another planet could pave the way for other advanced robotic flying vehicles.

Possible uses of a future helicopter on Mars include:

A unique viewpoint not provided by current orbiters, rovers or landers

High-definition images and reconnaissance for robots or humans

Access to terrain that is difficult for rovers to reach

Could even carry light but vital payloads from one site to another

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How the New Horizon’s flyby changed the way we see Pluto 💓 [NASA/JPL] 

What Separates A Good Scientific Theory From A Bad One?

“It’s why an idea like dark matter is so powerful. By adding just a single new species of particle — something that’s cold, collisionless, and transparent to light and normal matter — you can explain everything from rotating galaxies to the cosmic web, the fluctuations in the microwave background, galaxy correlations, colliding galaxy clusters, and much, much more. It’s why ideas with a huge number of free parameters that must be tuned to get the right results are less satisfying and less predictively powerful. If we can model dark energy, for instance, with just one constant, why would we invent multi-field models with many parameters that are no more successful?”

You’ve often heard, when discussing competing scientific ideas, of appealing to Occam’s razor. Often paraphrased as “all things being equal, the simplest explanation is usually best,” it seems to open the door for people to argue over which explanation is simplest. This should not, however, be a point of contention: the explanation that’s simplest is the one that introduces the fewest number of new, additional free parameters. And when it comes to all things being equal, the things in question ought to be the number of new phenomena the novel idea can explain, along with the number of discernible predictions as compared with the old, prevailing idea. The best scientific ideas are the ones that explain the most by adding the least, while the worst ones unnecessarily add additional parameters on top of what we observe for no good reason other than personal bias. Ideas may be a dime-a-dozen, but a good idea is hard to find.

The next time you encounter an interesting, wild idea that someone throws out there, use this criteria to evaluate it. You just might be surprised at how quickly you can tell whether an idea is good or bad!

Cassini Spacecraft: Top Discoveries

Our Cassini spacecraft has been exploring Saturn, its stunning rings and its strange and beautiful moons for more than a decade.

Having expended almost every bit of the rocket propellant it carried to Saturn, operators are deliberately plunging Cassini into the planet to ensure Saturn’s moons will remain pristine for future exploration – in particular, the ice-covered, ocean-bearing moon Enceladus, but also Titan, with its intriguing pre-biotic chemistry.

Let’s take a look back at some of Cassini’s top discoveries:  

Titan

Under its shroud of haze, Saturn’s planet-sized moon Titan hides dunes, mountains of water ice and rivers and seas of liquid methane. Of the hundreds of moons in our solar system, Titan is the only one with a dense atmosphere and large liquid reservoirs on its surface, making it in some ways more like a terrestrial planet.

Both Earth and Titan have nitrogen-dominated atmospheres – over 95% nitrogen in Titan’s case. However, unlike Earth, Titan has very little oxygen; the rest of the atmosphere is mostly methane and traced amounts of other gases, including ethane.

There are three large seas, all located close to the moon’s north pole, surrounded by numerous smaller lakes in the northern hemisphere. Just one large lake has been found in the southern hemisphere.

Enceladus

The moon Enceladus conceals a global ocean of salty liquid water beneath its icy surface. Some of that water even shoots out into space, creating an immense plume!

For decades, scientists didn’t know why Enceladus was the brightest world in the solar system, or how it related to Saturn’s E ring. Cassini found that both the fresh coating on its surface, and icy material in the E ring originate from vents connected to a global subsurface saltwater ocean that might host hydrothermal vents.

With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist.

Iapetus

Saturn’s two-toned moon Iapetus gets its odd coloring from reddish dust in its orbital path that is swept up and lands on the leading face of the moon.

The most unique, and perhaps most remarkable feature discovered on Iapetus in Cassini images is a topographic ridge that coincides almost exactly with the geographic equator. The physical origin of the ridge has yet to be explained…

It is not yet year whether the ridge is a mountain belt that has folded upward, or an extensional crack in the surface through which material from inside Iapetus erupted onto the surface and accumulated locally.

Saturn’s Rings

Saturn’s rings are made of countless particles of ice and dust, which Saturn’s moons push and tug, creating gaps and waves.

Scientists have never before studied the size, temperature, composition and distribution of Saturn’s rings from Saturn obit. Cassini has captured extraordinary ring-moon interactions, observed the lowest ring-temperature ever recorded at Saturn, discovered that the moon Enceladus is the source for Saturn’s E ring, and viewed the rings at equinox when sunlight strikes the rings edge-on, revealing never-before-seen ring features and details.

Cassini also studied features in Saturn’s rings called “spokes,” which can be longer than the diameter of Earth. Scientists think they’re made of thin icy particles that are lifted by an electrostatic charge and only last a few hours.  

Auroras

The powerful magnetic field that permeates Saturn is strange because it lines up with the planet’s poles. But just like Earth’s field, it all creates shimmering auroras.

Auroras on Saturn occur in a process similar to Earth’s northern and southern lights. Particles from the solar wind are channeled by Saturn’s magnetic field toward the planet’s poles, where they interact with electrically charged gas (plasma) in the upper atmosphere and emit light.  

Turbulent Atmosphere

Saturn’s turbulent atmosphere churns with immense storms and a striking, six-sided jet stream near its north pole.

Saturn’s north and south poles are also each beautifully (and violently) decorated by a colossal swirling storm. Cassini got an up-close look at the north polar storm and scientists found that the storm’s eye was about 50 times wider than an Earth hurricane’s eye.

Unlike the Earth hurricanes that are driven by warm ocean waters, Saturn’s polar vortexes aren’t actually hurricanes. They’re hurricane-like though, and even contain lightning. Cassini’s instruments have ‘heard’ lightning ever since entering Saturn orbit in 2004, in the form of radio waves. But it wasn’t until 2009 that Cassini’s cameras captured images of Saturnian lighting for the first time.

Cassini scientists assembled a short video of it, the first video of lightning discharging on a planet other than Earth.

Cassini’s adventure will end soon because it’s almost out of fuel. So to avoid possibly ever contaminating moons like Enceladus or Titan, on Sept. 15 it will intentionally dive into Saturn’s atmosphere.

The spacecraft is expected to lose radio contact with Earth within about one to two minutes after beginning its decent into Saturn’s upper atmosphere. But on the way down, before contact is lost, eight of Cassini’s 12 science instruments will be operating! More details on the spacecraft’s final decent can be found HERE.

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