Solar System: Things To Know This Week

Solar System: Things to Know This Week

Our solar system is a jewel box filled with a glittering variety of beautiful worlds–and not all of them are planets. This week, we present our solar system’s most marvelous moons.

1. Weird Weather: Titan

Saturn’s hazy moon Titan is larger than Mercury, but its size is not the only way it’s like a planet. Titan has a thick atmosphere, complete with its own “water cycle” – except that it’s way too cold on Titan for liquid water. Instead, rains of liquid hydrocarbons like ethane and methane fall onto icy mountains, run into rivers, and gather into great seas. Our Cassini spacecraft mapped the methane seas with radar, and its cameras even caught a glimpse of sunlight reflecting off the seas’ surface. Learn more about Titan: saturn.jpl.nasa.gov/science/titan/

2. Icy Giant: Ganymede

Jupiter’s moon Ganymede is the largest in the solar system. It’s bigger than Mercury and Pluto, and three-quarters the size of Mars. It’s also the only moon known to have its own magnetic field. Details: solarsystem.nasa.gov/planets/ganymede/indepth

3. Retrograde Rebel: Triton

Triton is Neptune’s largest moon, and the only one in the solar system to orbit in the opposite direction of its planet’s rotation, a retrograde orbit. It may have been captured from the Kuiper Belt, where Pluto orbits. Despite the frigid temperatures there, Triton has cryovolcanic activity – frozen nitrogen sometimes sublimates directly to gas and erupts from geysers on the surface. More on Triton: solarsystem.nasa.gov/planets/triton/indepth

4. Cold Faithful: Enceladus

The most famous geysers in our solar system (outside of those on Earth) belong to Saturn’s moon Enceladus. It’s a small, icy body, but Cassini revealed this world to be one of the solar system’s most scientifically interesting destinations. Geyser-like jets spew water vapor and ice particles from an underground ocean beneath the icy crust of Enceladus. With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist. Get the details: saturn.jpl.nasa.gov/science/enceladus/

5. Volcano World: Io

Jupiter’s moon Io is subjected to tremendous gravitational forces that cause its surface to bulge up and down by as much as 330 feet (100 m). The result? Io is the most volcanically active body in the Solar System, with hundreds of volcanoes, some erupting lava fountains dozens of miles high. More on Io’s volcanoes: solarsystem.nasa.gov/planets/io/indepth

6. Yin and Yang Moon: Iapetus

When Giovanni Cassini discovered Iapetus in 1671, he observed that one side of this moon of Saturn was bright and the other dark. He noted that he could only see Iapetus on the west side of Saturn, and correctly concluded that Iapetus had one side much darker than the other side. Why? Three centuries later, the Cassini spacecraft solved the puzzle. Dark, reddish dust in Iapetus’s orbital path is swept up and lands on the leading face of the moon. The dark areas absorb energy and become warmer, while uncontaminated areas remain cooler. Learn more: saturn.jpl.nasa.gov/news/2892/cassini-10-years-at-saturn-top-10-discoveries/#nine

7. A Double World: Charon and Pluto

At half the size of Pluto, Charon is the largest of Pluto’s moons and the largest known satellite relative to its parent body. The moon is so big compared to Pluto that Pluto and Charon are sometimes referred to as a double planet system. Charon’s orbit around Pluto takes 6.4 Earth days, and one Pluto rotation (a Pluto day) takes 6.4 Earth days. So from Pluto’s point of view Charon neither rises nor sets, but hovers over the same spot on Pluto’s surface, and the same side of Charon always faces Pluto. Get the details: www.nasa.gov/feature/pluto-and-charon-new-horizons-dynamic-duo

8. “Death Star” Moon: Mimas

Saturn’s moon Mimas has one feature that draws more attention than any other: the crater Herschel, which formed in an impact that nearly shattered the little world. Herschel gives Mimas a distinctive look that prompts an oft-repeated joke. But, yes, it’s a moon. More: olarsystem.nasa.gov/planets/mimas

9. Don’t Be Afraid, It’s Just Phobos

In mythology, Mars is a the god of war, so it’s fitting that its two small moons are called Phobos, “fear,” and Deimos, “terror.” Our Mars Reconnaissance Orbiter caught this look at Phobos, which is roughly 17 miles (27 km) wide. In recent years, NASA scientists have come to think that Phobos will be torn apart by its host planet’s gravity. Details: www.nasa.gov/feature/goddard/phobos-is-falling-apart

Learn more about Phobos: solarsystem.nasa.gov/planets/phobos/indepth

10. The Moon We Know Best

Although decades have passed since astronauts last set foot on its surface, Earth’s moon is far from abandoned. Several robotic missions have continued the exploration. For example, this stunning view of the moon’s famous Tycho crater was captured by our Lunar Reconnaissance Orbiter, which continues to map the surface in fine detail today. More: www.lroc.asu.edu/posts/902

Discover more lists of 10 things to know about our solar system HERE.

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Space Station Science: Biological Research

Each month, we highlight a different research topic on the International Space Station. In August, our focus is biological research. Learning how spaceflight affects living organisms will help us understand potential health risks related to humans on long duration missions, including our journey to Mars.

Cells, microbes, animals and plants are affected by microgravity, and studying the processes involved in adaptation to spaceflight increases our fundamental understanding of biological processes on Earth. Results on Earth from biological research in space include the development of new medications, improved agriculture, advancements in tissue engineering and regeneration, and more.

Take a look at a few of the biological research experiments performed on space station:

Biomolecule Sequencer

Living organisms contain DNA, and sequencing DNA is a powerful way to understand how they respond to changing environments. The Biomolecule Sequencer experiment hopes to demonstrate (for the first time) that DNA sequencing is feasible in an orbiting spacecraft. Why? A space-based DNA sequencer could identify microbes, diagnose diseases and understand crew member health, and potentially help detect DNA- based life elsewhere in the solar system.

Ant-stronauts

Yes, ant-stronauts…as in ants in space. These types of studies provide insights into how ants answer collective search problems. Watching how the colony adapts as a unit in the quest for resources in extreme environments, like space, provides data that can be used to build algorithms with varied applications. Understanding how ants search in different conditions could have applications for robotics.

TAGES

The TAGES experiment (Transgenic Arabidopsis Gene Expression System) looks to see how microgravity impacts the growth of plant roots. Fluorescent markers placed on the plant’s genes allow scientists to study root development of Arabidopsis (a cress plant) grown on the space station. Evidence shows that directional light in microgravity skews root growth to the right, rather than straight down from the light source. Root growth patters on station mimic that of plants grown at at 45% degree angle on Earth. Space flight appears to slow the rate of the plant’s early growth as well.

Heart Cells

Spaceflight can cause a suite of negative health effects, which become more problematic as crew members stay in orbit for long periods of time. Effects of Microgravity on Stem Cell-Derived Cardiomycytes (Heart Cells) studies the human heart, specifically how heart muscle tissue contracts, grows and changes in microgravity. Understanding how heart muscle cells change in space improves efforts for studying disease, screening drugs and conducting cell replacement therapy for future space missions.

Medaka Fish

Chew on these results…Jaw bones of Japanese Medaka fish in microgravity show decreased mineral density and increased volume of osteoclasts, cells that break down bone tissue. Results from this study improve our understanding of the mechanisms behind bone density and organ tissue changes in space.

These experiments, and many others, emphasize the importance of biological research on the space station. Understanding the potential health effects for crew members in microgravity will help us develop preventatives and countermeasures.

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bigbluenasa

9 years ago

What Have We Learned About Pluto?

This month (March 2016), in the journal Science, New Horizons scientists have authored the first comprehensive set of papers describing results from last summer’s Pluto system flyby. These detailed papers completely transform our view of Pluto and reveal the former “astronomer’s planet” to be a real world with diverse and active geology, exotic surface chemistry, a complex atmosphere, puzzling interaction with the sun and an intriguing system of small moons.

Here’s a breakdown of what we’ve learned about Pluto:

1. Pluto has been geologically active throughout the past 4 billion years. The age-dating of Pluto’s surface through crater counts has revealed that Pluto has been geologically active throughout the past 4 billion years. Further, the surface of Pluto’s informally-named Sputnik Planum, a massive ice plain larger than Texas, is devoid of any detectable craters and estimated to be geologically young – no more than 10 million years old.

2. Pluto’s moon Charon has been discovered to have an ancient surface. As an example, the great expanse of smooth plains on Charon is likely a vast cryovolcanic flow or flows that erupted onto Charon’s surface about 4 billion years ago. These flows are likely related to the freezing of an internal ocean that globally ruptured Charon’s crust.

3. Pluto’s surface has many types of terrain. The distribution of compositional units on Pluto’s surface – from nitrogen-rich, to methane-rich, to water-rich – has been found to be surprisingly complex, creating puzzles for understanding Pluto’s climate and geologic history. The variations in surface composition on Pluto are unprecedented elsewhere in the outer solar system.

4. Pluto’s atmosphere is colder than we thought. Pluto’s upper atmospheric temperature has been found to be much colder (by about 70 degrees Fahrenheit) than had been thought from Earth-based studies, with important implications for its atmospheric escape rate. Why the atmosphere is colder is a mystery.

5. We know what Pluto’s atmosphere is made of. The New Horizon spacecraft made observations of sunlight passing through Pluto’s atmosphere. We see absorption features that indicate an atmosphere made up of nitrogen (like Earth’s) with methane, acetylene and ethylene as minor constituents.

6. We might have an idea for how Pluto’s haze formed. For first time, a plausible mechanism for forming Pluto’s atmospheric haze layers has been found. This mechanism involves the concentration of haze particles by atmospheric buoyancy waves, created by winds blowing over Pluto’s mountainous topography. Pluto’s haze extends hundreds of kilometers into space, and embedded within it are over 20 very thin, but far brighter, layers.

7. There isn’t much dust around Pluto. Before the flyby, there was concern that a small piece of debris (even the size of a grain of sand) could cause great damage to (or even destroy) the spacecraft. But the Venetia Burney Student Dust Counter (an instrument on the New Horizons spacecraft) only counted a single dust particle within five days of the flyby. This is similar to the density of dust particles in free space in the outer solar system – about 6 particles per cubic mile – showing that the region around Pluto is, in fact, not filled with debris.

8. Pluto’s atmosphere is smaller than we expected. The uppermost region of Pluto’s atmosphere is slowly escaping to space. The hotter the upper atmosphere, the more rapid the gasses escape. The lower the planet’s mass, the lower the gravity, and the faster the atmospheric loss. As molecules escape, they are ionized by solar ultraviolet light. Once ionized, the charged molecules are carried away by the solar wind. As more Pluto-genic material is picked up by the solar wind, the more the solar wind is slowed down and deflected around Pluto. So - the net result is a region (the interaction region), which is like a blunt cone pointed toward the sun, where the escaping ionized gasses interact with the solar wind. The cone extends to a distance about 6 Pluto radii from Pluto toward the sun, but extend behind Pluto at least 400 Pluto radii behind Pluto - like a wake behind the dwarf planet.

9. Pluto’s moons are brighter than we thought. The high albedos (reflectiveness) of Pluto’s small satellites (moons) – about 50 to 80 percent – are entirely different from the much lower reflectiveness of the small bodies in the general Kuiper Belt population, which range from about 5 to 20 percent. This difference lends further support to the idea that these moons were not captured from the general Kuiper Belt population, but instead formed by the collection of material produced in the aftermath of the giant collision that created the entire Pluto satellite system.

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bigbluenasa

9 years ago

SVS: Dust in the Wind

Ever been wowed by a NASA science visualization? Learn about their creation from NASA technical artist Kel Elkins. @NASAEPDC

Small Tissue Chips in Space a Big Leap Forward for Research

Tissue chips, thumb-drive sized devices that contain human cells in a 3D matrix, represent a giant leap in science.

They can test cells’ response to:

•stresses

•drugs

•genetic changes

The Tissue Chips in Space initiative seeks to better understand the role of microgravity on human health and disease and to translate that understanding to improved human health on Earth.

This series of investigations to test tissue chips in microgravity aboard the International Space Station is planned through a collaboration between the National Center for Advancing Translational Sciences (NCATS) at the National Institutes for Health (NIH) and the National Laboratory in partnership with NASA.

Many of the changes in the human body caused by microgravity resemble the onset and progression of diseases associated with aging on Earth, but in space, changes occur much faster. Scientists may be able to use tissue chips in space to model changes that take months or years to happen on Earth.

A tissue chip needs three properties, according to Lucie Low, scientific program manager at NCATS. “It has to be 3D,” she explained. “It must have multiple different types of cells, and it must have microfluidic channels. Essentially, you get a functional unit of what human tissues are like, outside of the body,” said Low.

As accurate models of the structure and function of human organs, tissue chips provide a model for predicting whether a drug, vaccine or biologic agent is safe in humans more quickly and effectively than current methods.

This first phase of Tissue Chips in Space includes five investigations. An investigation of immune system aging is planned for launch on the SpaceX CRS-16 flight, scheduled for mid-November. The other four, scheduled to launch on subsequent flights, include lung host defense, the blood-brain barrier, musculoskeletal disease and kidney function. This phase tests the effects of microgravity on the tissue chips and demonstrates the capability of the automated system.

All five investigations make a second flight about 18 months later to confirm use of the model, such as testing potential drugs on the particular organs. Four more projects are scheduled for launch in summer 2020, including two on engineered heart tissue to understand cardiovascular health, one on muscle wasting and another on gut inflammation.

Ultimately, the technology could allow astronauts going into space to take along personalized chips that could be used to monitor changes in their bodies and to test possible countermeasures and therapies. That would be a major leap forward in keeping astronauts healthy on missions to deep space!

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