Siesta (by Big Andrei)

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Geminid Meteors over Chile

Image Credit & Copyright: Yuri Beletsky (Las Campanas Observatory, Carnegie Institution)

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Be Glad You Don’t Have to Dust in Space!

Throw open the windows and break out the feather duster, because spring is here and it’s time to do a little cleaning! Fortunately, no one has to tidy up the dust in space — because there’s a lot of it — around 100 tons rain down on Earth alone every day! And there’s even more swirling around the solar system, our Milky Way galaxy, other galaxies and the spaces in between. 

By studying the contents of the dust in your house — which can include skin cells, pet fur, furniture fibers, pollen, concrete particles and more — scientists learn a lot about your environment. In the same way, scientists can learn a lot by looking at space dust. Also called cosmic dust, a fleck of space dust is usually smaller than a grain of sand and is made of rock, ice, minerals or organic compounds. Scientists can study cosmic dust to learn about how it formed and how the universe recycles material.

“We are made of star-stuff,” Carl Sagan famously said. And it’s true! When a star dies, it sheds clouds of gas in strong stellar winds or in an explosion called a supernova. As the gas cools, minerals condense. Recent observations by our SOFIA mission suggest that in the wake of a supernova shockwave, dust may form more rapidly than scientists previously thought. These clouds of gas and dust created by the deaths of stars can sprawl across light-years and form new stars — like the Horsehead Nebula pictured above. Disks of dust and gas form around new stars and produce planets, moons, asteroids and comets. Here on Earth, some of that space dust eventually became included in living organisms — like us! Billions of years from now, our Sun will die too. The gas and dust it sheds will be recycled into new stars and planets and so on and so forth, in perpetuity!

Astronomers originally thought dust was a nuisance that got in the way of seeing the objects it surrounded. Dust scatters and absorbs light from stars and emits heat as infrared light. Once we started using infrared telescopes, we began to understand just how important dust is in the universe and how beautiful it can be. The picture of the Andromeda galaxy above was taken in the infrared by our Spitzer Space Telescope and reveals detailed spirals of dust that we can’t see in an optical image.

We also see plenty of dust right here in our solar system. Saturn’s rings are made of mostly ice particles and some dust, but scientists think that dust from meteorites may be darkening the rings over time. Jupiter also has faint dusty rings, although they’re hard to see — Voyager 1 only discovered them when it saw them backlit by the Sun. Astronomers think the rings formed when meteorite impacts on Jupiter’s moons released dust into orbit. The Juno spacecraft took the above picture in 2016 from inside the rings, looking out at the bright star Betelgeuse.

Copyright Josh Calcino, used with permission

And some space dust you can see from right here on Earth! In spring or autumn, right before sunrise or after sunset, you may be able to catch a glimpse of a hazy cone of light above the horizon created when the Sun’s rays are scattered by dust in the inner solar system. You can see an example in the image above, extending from above the tree on the horizon toward a spectacular view of the Milky Way. This phenomenon is called zodiacal light — and the dust that’s reflecting the sunlight probably comes from icy comets. Those comets were created by the same dusty disk that that formed our planets and eventually you and the dust under your couch!

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Ten interesting facts about Jupiter

Here is a list of some interesting facts about the planet Jupiter. A planet that catches the attention of all, by its size, storms and its surprising moons.

The mass of Jupiter is 318 times as massive as the Earth. In fact, Jupiter is 2.5 times more massive than all of the other planets in the Solar System combined.

Its gravity is so strong that a rocket would have to go an unthinkable 135,000 mph to leave.

The Great Red Spot on Jupiter is one of its most familiar features. This persistent anticyclonic storm, which is located south of its equator, measures between 24,000 km in diameter and 12–14,000 km in height. As such, it is large enough to contain two or three planets the size of Earth’s diameter. And the spot has been around for at least 350 years, since it was spotted as far back as the 17th century.

Jupiter’s rings were discovered in 1979 by the passing Voyager 1 spacecraft, but their origin was a mystery. Data from the Galileo spacecraft that orbited Jupiter from 1995 to 2003 later confirmed that these rings were created by meteoroid impacts on small nearby moons.

Extending up to seven million kilometers in the Sun’s direction and almost to the orbit of Saturn in the opposite direction, Jupiter’s magnetosphere is the largest and most powerful of any planetary magnetosphere in the Solar System, and by volume the largest known continuous structure in the Solar System after the heliosphere.

Jupiter has a total of 69 natural satellites. The four largest are: Io, Europa, Ganymede and Callisto. However, it is estimated that the planet has over 200 natural satellites orbiting it. Almost all of them are less than 10 kilometers in diameter, and were only discovered after 1975, when the first spacecraft (Pioneer 10) arrived at Jupiter.

Jupiter Has Been Visited 8 Times By Spacecraft. Jupiter was first visited by NASA’s Pioneer 10 spacecraft in December 1973, and then Pioneer 11 in December 1974. Then came the Voyager 1 and 2 flybys, both of which happened in 1979. This was followed by a long break until Ulysses arrived in February 1992, followed by the Galileo space probe in 1995. Then Cassini made a flyby in 2000, on its way to Saturn. And finally, NASA’s New Horizons spacecraft made its flyby in 2007. NASA’s Juno spacecraft is currently orbiting Jupiter.

Jupiter is the third brightest object in the Solar System, after Venus and the Moon.

Jupiter Is The Fastest Spinning Planet In The Solar System. For all its size and mass, Jupiter sure moves quickly. In fact, with an rotational velocity of 12.6 km/s (~7.45 m/s) or 45,300 km/h (28,148 mph), the planet only takes about 10 hours to complete a full rotation on its axis. And because it’s spinning so rapidly, the planet has flattened out at the poles a little and is bulging at its equator.

Jupiter Cannot Become A Star. Astronomers call Jupiter a failed star, but that’s not really an appropriate description. While it is true that, like a star, Jupiter is rich in hydrogen and helium, Jupiter does not have nearly enough mass to trigger a fusion reaction in its core. This is how stars generate energy, by fusing hydrogen atoms together under extreme heat and pressure to create helium, releasing light and heat in the process.

This is made possible by their enormous gravity. For Jupiter to ignite a nuclear fusion process and become a star, it would need more than 70 times its current mass. If you could crash dozens of Jupiters together, you might have a chance to make a new star. But in the meantime, Jupiter shall remain a large gas giant with no hopes of becoming a star. Sorry, Jupiter!

Sources: universetoday and wikipedia

Images credits: Wikimedia Commons, JAXA, NASA, ESA, Hubble, Wang Letian & Michael Carroll

#Cool

What’s Enceladus?

Before we tell you about Enceladus, let’s first talk about our Cassini spacecraft…

Our Cassini mission to Saturn is one of the most ambitious efforts in planetary space exploration ever mounted. Cassini is a sophisticated robotic spacecraft orbiting the ringed planet and studying the Saturnian system in detail.

Cassini completed its initial four-year mission to explore the Saturn System in June 2008. It has also completed its first mission extension in September 2010. Now, the health spacecraft is making exciting new discoveries in a second extension mission!

Enceladus

Enceladus is one of Saturn’s many moons, and is one of the brightest objects in our solar system. This moon is about as wide as Arizona, and displays at least five different types of terrain. The surface is believed to be geologically “young”, possibly less than 100 million years old.

Cassini first discovered continually-erupting fountains of icy material on Enceladus in 2005. Since then, the Saturn moon has become one of the most promising places in the solar system to search for present-day habitable environments.  

Scientists found that hydrothermal activity may be occurring on the seafloor of the moon’s underground ocean. In September, it was announced that its ocean –previously thought to only be a regional sea – was global!

Since Cassini is nearing the end of its mission, we are able to make a series of three close encounters with Enceladus, one of Saturn’s moons.

Close Encounters

On Oct. 14, Cassini performed a mid-range flyby of Enceladus, but the main event will take place on Oct. 28, when Cassini will come dizzyingly close to the icy moon. During this flyby, the spacecraft will pass a mere 30 miles above the moon’s south polar region!

This will be the deepest-ever dive through the moon’s plume of icy spray, where Cassini can collect images and valuable data about what’s going on beneath the frozen surface.

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