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Going for GOLD

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Going for GOLD

On Jan. 25, we’re going for GOLD!

We’re launching an instrument called Global-scale Observations of the Limb and Disk, GOLD for short. It’s a new mission that will study a complicated — and not yet fully understood — region of near-Earth space, called the ionosphere.

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Space is not completely empty: It’s teeming with fast-moving energized particles and electric and magnetic fields that guide their motion. At the boundary between Earth’s atmosphere and space, these particles and fields — the ionosphere — co-exist with the upper reaches of the neutral atmosphere.

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That makes this a complicated place. Big events in the lower atmosphere, like hurricanes or tsunamis, can create waves that travel all the way up to that interface to space, changing the wind patterns and causing disruptions.

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It’s also affected by space weather. The Sun is a dynamic star, and it releases spurts of energized particles and blasts of solar material carrying electric and magnetic fields that travel out through the solar system. Depending on their direction, these bursts have the potential to disrupt space near Earth.

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This combination of factors makes it hard to predict changes in the ionosphere — and that can have a big impact. Communications signals, like radio waves and signals that make our GPS systems work, travel through this region, and sudden changes can distort them or even cut them off completely.

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Low-Earth orbiting satellites — including the International Space Station — also fly through the ionosphere, so understanding how it fluctuates is important for protecting these satellites and astronauts.  

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GOLD is a spectrograph, an instrument that breaks light down into its component wavelengths, measuring their intensities. Breaking light up like this helps scientists see the behavior of individual chemical elements — for instance, separating the amount of oxygen versus nitrogen. GOLD sees in far ultraviolet light, a type of light that’s invisible to our eyes.

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GOLD is a hosted payload. The instrument is hitching a ride aboard SES-14, a commercial communications satellite built by Airbus for SES Government Solutions, which owns and operates the satellite.

Also launching this year is the Ionospheric Connection Explorer, or ICON, which will also study the ionosphere and neutral upper atmosphere. But while GOLD will fly in geostationary orbit some 22,000 miles above the Western Hemisphere, ICON will fly just 350 miles above Earth, able to gather close up images of this region.

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Together, these missions give us an unprecedented look at the ionosphere and upper atmosphere, helping us understand the very nature of how our planet interacts with space.

To learn more about this region of space and the GOLD mission, visit: nasa.gov/gold.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.  

Source: NASA


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What’s Up – January 2018

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What’s Up – January 2018

What’s Up For January? 

Quadrantid meteors, a West Coast-favoring total lunar eclipse and time to start watching Mars!

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This month the new year’s first meteor shower fizzles, Mars meets Jupiter in the morning sky and the U.S. will enjoy a total lunar eclipse!

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Most meteor showers radiate from recognizable constellations. Like the Leonids, Geminids and Orionids.

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But the Quadrantids are meteors that appear to radiate from the location of the former Quadrans Muralis constellation, an area that’s now part of the constellation Bootes.

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The Quadrantids’ peak lasts for just a few hours, and sadly, this year their timing coincides with a very bright, nearly full moon that will wash out most of the meteors.

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You can look in any direction to see all the meteor showers. When you see one of these meteors, hold a shoestring along the path it followed. The shoestring will lead you back to the constellation containing the meteor’s origin.

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On the morning of January 6th, look in the south-southeast sky 45 minutes before sunrise to see Jupiter and fainter Mars almost as close as last month’s Jupiter and Venus close pairing.

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Mars is only one-sixth the apparent diameter of Jupiter, but the two offer a great binocular and telescopic view with a pretty color contrast. They remain in each other’s neighborhood from January 5th through the 8th.

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Finally, to end the month, a great total lunar eclipse favors the western U.S., Alaska, and Hawaii and British Columbia on January 31st. Australia and the Pacific Ocean are well placed to see a major portion of the eclipse–if not all of it.

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Watch the full What’s Up for January Video: 

There are so many sights to see in the sky. To stay informed, subscribe to our What’s Up video series on Facebook.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.   

Source: NASA


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The Moon in Motion

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The Moon in Motion

Happy New Year! And happy supermoon! Tonight, the Moon will appear extra big and bright to welcome us into 2018 – about 6% bigger and 14% brighter than the average full Moon. And how do we know that? Well, each fall, our science visualizer Ernie Wright uses data from the Lunar Reconnaissance Orbiter (LRO) to render over a quarter of a million images of the Moon. He combines these images into an interactive visualization, Moon Phase and Libration, which depicts the Moon at every day and hour for the coming year. 

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Want to see what the Moon will look like on your birthday this year? Just put in the date, and even the hour (in Universal Time) you were born to see your birthday Moon.

Our Moon is quite dynamic. In addition to Moon phases, our Moon
appears to get bigger and smaller throughout the year, and it wobbles! Or at
least it looks that way to us on Earth. This wobbling is called libration, from
the Latin for ‘balance scale’ (libra). Wright relies on LRO maps of the Moon
and NASA orbit calculations to create the most accurate depiction of the 6 ways
our Moon moves from our perspective.

1. Phases

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The Moon phases we see on Earth are caused by the
changing positions of the Earth and Moon relative to the Sun. The Sun always
illuminates half of the Moon, but we see changing shapes as the Moon revolves
around the Earth. Wright uses a our software library called SPICE to calculate
the position and orientation of the Moon and Earth at every moment of the year. With his
visualization, you can input any day and time of the year and see what the Moon
will look like!

2. Shape of the Moon

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Check out that crater detail! The Moon is not a smooth sphere.
It’s covered in mountains and valleys and thanks to LRO, we know the shape of
the Moon better than any other celestial body in the universe. To get the most
accurate depiction possible of where the sunlight falls on the lunar surface
throughout the month, Wright uses the same graphics software used by Hollywood
design studios, including Pixar, and a method called ‘raytracing’ to calculate
the intricate patterns of light and shadow on the Moon’s surface, and he checks
the accuracy of his renders against photographs of the Moon he takes through
his own telescope.

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3. Apparent Size 

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The
Moon Phase and Libration visualization shows you the apparent size of the Moon.
The Moon’s orbit is elliptical, instead of circular – so sometimes it is closer
to the Earth and sometimes it is farther. You’ve probably heard the term
supermoon.” This describes a full Moon at perigee (the point when the Moon is
closest to the Earth in its orbit). A supermoon can appear up to 14% bigger and brighter
than a full Moon at apogee (the point when the Moon is farthest from the Earth
in its orbit). 

Our supermoon tonight is a full Moon very close to perigee, and will appear to be about 14% bigger than the July 27 full Moon, the smallest full Moon of
2018, occuring at apogee. Input those dates into the Moon Phase and Libration visualization to see this difference in apparent size!

4. East-West Libration

Over a month, the Moon appears to nod, twist, and roll. The
east-west motion, called ‘libration in longitude’, is another effect of the
Moon’s elliptical orbital path. As the Moon travels around the Earth, it goes
faster or slower, depending on how close it is to the Earth. When the Moon gets
close to the Earth, it speeds up thanks to a push from Earth’s gravity. Then it
slows down, when it’s farther from the Earth. While this speed in orbital
motion changes, the rotational speed of the Moon stays constant. 

This means
that when the Moon moves faster around the Earth, the Moon itself doesn’t rotate
quite enough to keep the same exact side facing us and we get to see a little
more of the eastern side of the Moon. When the Moon moves more slowly around
the Earth, its rotation gets a little ahead, and we see a bit more of its
western side.

5. North-South Libration

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The
Moon also appears to nod, as if it were saying “yes,” a motion called
‘libration in latitude’. This is caused by the 5 degree tilt of the Moon’s
orbit around the Earth. Sometimes the Moon is above the Earth’s northern
hemisphere and sometimes it’s below the Earth’s southern hemisphere, and this
lets us occasionally see slightly more of the northern or southern hemispheres
of the Moon! 

6. Axis Angle

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Finally, the Moon appears to tilt back and forth like a metronome.
The tilt of the Moon’s orbit contributes to this, but it’s mostly because of
the 23.5 degree tilt of our own observing platform, the Earth. Imagine standing
sideways on a ramp. Look left, and the ramp slopes up. Look right and the ramp
slopes down. 

Now look in front of you. The horizon will look higher on the
right, lower on the left (try this by tilting your head left). But if you turn
around, the horizon appears to tilt the opposite way (tilt your head to the
right). The tilted platform of the Earth works the same way as we watch the
Moon. Every two weeks we have to look in the opposite direction to see the
Moon, and the ground beneath our feet is then tilted the opposite way as well.

So put this all together, and you get this:

Beautiful isn’t it? See if you can notice these phenomena when you observe the Moon. And keep coming back all year to check on the Moon’s changing appearance and help plan your observing sessions.

Follow
@NASAMoon on Twitter to keep up with the latest lunar updates. 

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Source: NASA


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