News | August 17, 2017
Scientists Improve Brown Dwarf Weather Forecasts
Dim objects called brown dwarfs, less massive than the Sun but more massive
than Jupiter, have powerful winds and clouds -- specifically, hot patchy clouds
made of iron droplets and silicate dust. Scientists recently realized these giant
clouds can move and thicken or thin surprisingly rapidly, in less than an Earth day,
but did not understand why.
Now, researchers have a new model for explaining how clouds move
and change shape in brown dwarfs, using insights from NASA's Spitzer Space Telescope.
Giant waves cause large-scale movement of particles
in brown dwarfs' atmospheres, changing the thickness
of the silicate clouds, researchers report in the journal Science.
The study also suggests these clouds are organized in bands confined
to different latitudes, traveling with different speeds in different bands.
"This is the first time we have seen atmospheric bands and waves
in brown dwarfs," said lead author Daniel Apai, associate professor
of astronomy and planetary sciences at the University of Arizona in Tucson.
Just as in Earth's ocean, different types of waves can form
in planetary atmospheres. For example, in Earth's atmosphere,
very long waves mix cold air from the polar regions to mid-latitudes,
which often lead clouds to form or dissipate.
The distribution and motions of the clouds on brown dwarfs in
this study are more similar to those seen on Jupiter, Saturn,
Uranus and Neptune. Neptune has cloud structures that
follow banded paths too, but its clouds are made of ice.
Observations of Neptune from NASA's Kepler spacecraft,
operating in its K2 mission, were important in this comparison
between the planet and brown dwarfs.
"The atmospheric winds of brown dwarfs seem to be more like
Jupiter's familiar regular pattern of belts and zones than
the chaotic atmospheric boiling seen on the Sun and many
other stars," said study co-author Mark Marley at NASA's Ames
Research Center in California's Silicon Valley.
Brown dwarfs can be thought of as failed stars because
they are too small to fuse chemical elements in their cores.
They can also be thought of as "super planets" because
they are more massive than Jupiter, yet have roughly the same
diameter. Like gas giant planets, brown dwarfs are mostly made
of hydrogen and helium, but they are often found apart from
any planetary systems. In a 2014 study using Spitzer, scientists found
that brown dwarfs commonly have atmospheric storms.
Due to their similarity to giant exoplanets, brown dwarfs are
windows into planetary systems beyond our own. It is easier
to study brown dwarfs than planets because they often do
not have a bright host star that obscures them.
"It is likely the banded structure and large atmospheric waves
we found in brown dwarfs will also be common in giant exoplanets,"
Apai said.
Using Spitzer, scientists monitored brightness changes in six
brown dwarfs over more than a year, observing each of them rotate
32 times. As a brown dwarf rotates, its clouds move in and out
of the hemisphere seen by the telescope, causing changes
in the brightness of the brown dwarf. Scientists then analyzed
these brightness variations to explore how silicate clouds are
distributed in the brown dwarfs.
Researchers had been expecting these brown dwarfs to have elliptical
storms resembling Jupiter's Great Red Spot, caused by high-pressure zones.
The Great Red Spot has been present in Jupiter for hundreds of years
and changes very slowly: Such "spots" could not explain the rapid changes
in brightness that scientists saw while observing these brown dwarfs.
The brightness levels of the brown dwarfs varied markedly just over
the course of an Earth day.
To make sense of the ups and downs of brightness, scientists had
to rethink their assumptions about what was going on in the brown dwarf
atmospheres. The best model to explain the variations involves large waves,
propagating through the atmosphere with different periods. These waves
would make the cloud structures rotate with different speeds in different bands.
University of Arizona researcher Theodora Karalidi used a supercomputer
and a new computer algorithm to create maps of how clouds travel
on these brown dwarfs.
"When the peaks of the two waves are offset, over the course
of the day there are two points of maximum brightness," Karalidi said.
"When the waves are in sync, you get one large peak, making
the brown dwarf twice as bright as with a single wave."
The results explain the puzzling behavior and brightness changes
that researchers previously saw. The next step is to try to better
understand what causes the waves that drive cloud behavior.
JPL manages the Spitzer Space Telescope mission for NASA's Science
Mission Directorate, Washington. Science operations are conducted
at the Spitzer Science Center at Caltech in Pasadena, California.
Spacecraft operations are based at Lockheed Martin Space Systems
Company, Littleton, Colorado. Data are archived at the Infrared Science
Archive housed at the Infrared Processing and Analysis Center at Caltech.
Caltech manages JPL for NASA. For more information about Spitzer, visit:
http://spitzer.caltech.eduhttps://www.nasa.gov/spitzerNews Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
https://www.jpl.nasa.gov/news/news.php?feature=6925&utm_source=iContact&utm_medium=email&utm_campaign=NASAJPL&utm_content=spitzer20170817-------------------------------------
Energy and Environment
What it’s like to ride a 6,000-ton icebreaker through Arctic waters
The Northwest Passage in 2017: Follow our series exploring the Arctic
By Chris Mooney August 14
elizabeth.landau@jpl.nasa.gov2017-221
VICTORIA STRAIT, NORTHWEST PASSAGE — When the CCGS Amundsen
breaks through a 10-foot (or thicker) piece of ice, it rides on top of it first,
the whole front of the ship sliding onto the sheet as the boat comes to a stop.
Then the ship, 100 yards long and weighing 6,000 tons, crushes down,
and its sharp hull splits the ice and pushes the fragments to either side.
Here in the ice-clogged Victoria Strait, there’s much crushing to do.
These are the icy waters that famously claimed the ships of
Sir John Franklin in the late 1840s, even though he set out
with Britain’s strongest steam-powered vessels of the time —
and, climate change or not, they don’t feel so different today.
The Washington Post’s Alice Li and I are here to document
a voyage of the CCGS Amundsen — a ship so famous in Canada
that it is pictured on the $50 bill — as it navigates the waterways
of the famous Northwest Passage. The boat is occupied by Canadian
coast guard sailors and dozens of scientists from the ArcticNet
consortium based at Université Laval in Quebec City.
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Your daily guide to the energy and environment debate.
The vessel’s crew and passengers are here researching how
the waters of the Arctic are changing because of climate change
and increased vessel traffic.
It’s a research mission that often involves impressive
and expensive instruments, such as the gigantic 35-foot-long
piston corer that plunges into the seafloor at high speed
and extracts long cylinders of ancient mud, looking
for clues on this environment’s state thousands
of years ago, when it was covered with a sheet of ice.
They also use a tool known as the CTD Rosette, a device consisting
of dozens of canisters that gathers up water samples to determine
basic physical properties of the ocean, checking temperatures
and salt levels as researchers investigate whether the seas
are warming or currents are shifting.
But the Amundsen is also a coast guard ship and at any moment
can be diverted from scientific pursuits to search and rescue,
or to help out a vessel in need. Several days ago, we took
a detour to provide some extra fuel and food to the U.S. Coast
Guard Cutter Maple, which is making a Northwest Passage transit
of its own — from Sitka, Alaska, to Baltimore — and needed a little
extra supplies along the way. That resulted in a touching moment
in which Canadian and U.S. personnel lined up on opposite decks
to swap T-shirts, baseball caps and even a book.
And it’s not just coast-guard callings that can rapidly change
the day’s plans — it’s the elements. Ice conditions are monitored
in high detail, often via the ship’s helicopter, sent to gather knowledge
far beyond what’s available from the official ice charts. As results come back,
science schedules are constantly being torn up and rewritten.
“We try to accommodate all the science that we can, but then fog
and ice and all these other variables that we have no control over,
they chew on our contingency time,” says Martine Lizotte,
the chief scientist on board and a research associate at the Université Laval
in Quebec City. “And if we add something to the schedule, like breaking ice,
then we have to subtract something else down the line.”
Jasmin Beauregard, left, and Hugo Jacques of the Canadian coast guard
prepare nets Wednesday in the Queen Maud Gulf. The nets are used
to scrape the seafloor and capture specimens for researchers to study.
(Alice Li/The Washington Post)
But the coast guard also benefits from having the scientists on board
because it pushes it to explore areas that aren’t otherwise immediate
coast guard priorities, said the ship’s commanding officer, Claude Lafrance.
“We usually go where the communities are or where the commercial
ship goes,” Lafrance said. “If we did not have the ArcticNet and
the scientists, the Arctic waters would stay with a lot of places
uncharted or not known.”
In between stops, the scientists grab sleep when they can —
they often hit their research sites in the wee hours of the morning
and quickly throw their equipment over the side. There’s plenty
of light to work by during those early hours, with the long hours
of light from the summer Arctic sun. But the schedule does mean people
on board are often tired, or at least keeping unusual sleep schedules.
The boat is filled more with students and graduate students
than senior scientists — getting much-needed experience
in taking cores from the seafloor or water samples. While on
the deck working with the heavy equipment, they wear hard hats,
steel-toed boots and “immersion” suits that remind you a little
of Luke Skywalker’s flight suit. The suits are there to keep you alive
if you fall into the freezing waters, long enough for someone to rescue you.
When the students aren’t working on the deck or in specialized labs
hosted in containers on the ship, they organized a scavenger hunt,
ranging around the ship and looking at scientific posters and
other displays to gather a list of information.
Life on board is modern and comfortable — the ship offers warm
showers, expertly cooked food by a trio of Quebecoise chefs,
and even hot chocolate when you come in from the cold and ice.
There’s a small gym and informally organized yoga classes.
There’s even formal Sunday dinner, where you’re supposed to get
out of muddy science clothes and dress nice. In the officer’s dining hall,
food and wine is served by a waitstaff. It’s all too easy to forget
you’re in remote, rarely visited and dangerous waters.
Time on board is punctuated by loudspeaker announcements from
the bridge, always in French first followed by English.
(The Amundsen’s home port is Quebec City.) One of the most common is a warning
not to smoke outside, because the helicopter is refueling — followed by
a subsequent announcement when the refueling is done and smoking can resume.
Rarer, and far more anticipated, announcements alert all on board
to the sighting of a polar bear or walrus perched on the ice.
So far we have seen several — including a bear whose enormous
head protruded from the water between ice floes as it swam in place
and seemed to be bathing.
Aude Boivin-Rioux teaches yoga in the officer’s lounge Saturday.
(Alice Li/The Washington Post)
Sleeping on board is in bunks, two to a cabin — and often done
despite the steady chirping sound of the echo sounder, which is
busy measuring the ocean floor and sediments beneath the ship
through the use of sound waves. You get used to it, or you find
earplugs.
The ship’s dramatic shaking at night as it crushes through thick ice
is ultimately a bit more unnerving. But the consolation is remembering
that you’re on a vessel designed for just this — and one that goes out
to rescue other ships that get in trouble in these waters.
A successful scientific cruise, Lizotte said, can be measured
in many ways. It could be gauged by how many research stops
are actually completed — but some are inevitably thwarted by the ice.
“But there’s also the human side of things, when you get off the ship
and people are like, ‘I’ll call you,’ and we’ll meet and we have a beer,”
she said.
“We’ve developed bonds, and we meet after these cruises.
I think that’s also a measure of success.”
Read more:
https://www.washingtonpost.com/news/energy-environment/wp/2017/08/14/what-its-like-to-ride-a-6000-ton-icebreaker-through-arctic-waters/?utm_term=.13774ffd134dThe Arctic’s fabled passage is opening up. This is what it looks like.
Even small boats are tackling the fabled Northwest Passage. The ice doesn’t always cooperate.
---------------------------------
LE CLANS DES MOUETTES AVEC LA N.A.S.A APPRENEZ L'ANGLAIS
ET SES VARIATIONS AFIN DE FAIRE DÉVELOPPER LE FRANÇAIS ET SES BRANCHAGES...
CITOYEN TIGNARD YANIS.
STEM Activities | NASA/JPL Edu
Teach
Bring the wonder of space to your students. Explore our universe
of science, technology, engineering and math activities and resources.
https://www.jpl.nasa.gov/edu/teach/Teachable Moments| August 10, 2017
Get Students Excited About Science With This Month’s Total Solar Eclipse
By Lyle Tavernier
Update – Aug. 17, 2017: Two new lessons ("Measuring Solar Energy
During an Eclipse" and "Modeling the Earth-Moon System") were
added to the Teach It section below.
In the News
A satellite image of the Moon's shadow on Earth during a total solar eclipse
The Moon casts a shadow on Earth during a total solar eclipse
over Europe in this image taken by a French astronaut
on the Mir Space Station. Credit: CNES
This month marks the first time in 38 years that one
of nature’s most awe-inspiring sights, a total solar eclipse,
will be visible from the continental United States. And unlike
the 1979 eclipse, the one on August 21 can be seen from coast to coast
– something that hasn’t happened since 1918.
Millions of people are expected to travel to the 14 states
that are in the path of totality – where the Moon will completely
cover the disk of the Sun – while hundreds of millions more
in every other state of the U.S. will be able to see a partial eclipse.
Whether you live in or are traveling to the path of totality,
or will be able to step outside and view the partial eclipse from
the comfort of your own home or school, the eclipse provides
both an inspiring reason to look to the sky and opportunities
to engage in scientific observations and discovery.
Animation of the Aug. 21, 2017 eclipse –
Pi in the Sky 4 math problem
Teach It
Use these standards-aligned lessons and related activities
to get your students excited about the eclipse
and the science that will be conducted during the eclipse.
› Get started!
How it Works
Eclipses occur as the result of an alignment between the Sun,
the Moon and Earth. Solar eclipses can only happen during
the new moon phase, when the Moon’s orbit brings it between
Earth and the Sun. At this time, the shadow cast by the moon
could land on Earth, resulting in an eclipse. But most of the time,
because the moon’s orbit is slightly titled, the moon’s shadow
falls above or below Earth.
The time period when the Moon, Earth and the Sun are lined up
and on the same plane is called an eclipse season. Eclipse seasons
last about 34 days and occur just shy of every six months.
A new moon during an eclipse season will cause the Moon’s shadow
to fall on Earth, creating a solar eclipse.
graphic showing eclipse seasons
An eclipse season is the time period when the Moon,
Earth and the Sun are lined up on the same plane.
A new moon during an eclipse season will cause the Moon's shadow
to fall on Earth, creating a solar eclipse. Image credit: NASA/JPL-Caltech
In addition to the proper alignment required for an eclipse, the distance
between Earth, the Moon and the Sun also plays an important role.
Even though the Moon is much smaller than
Sun (about 400 times smaller in diameter), the Sun and Moon appear
about the same size from Earth because the Sun is about 400 times
farther away than the Moon. If the Moon were farther from Earth,
it would appear smaller and not cover the disk of the Sun. Similarly,
if the Sun were closer to Earth, it would appear larger and the Moon
would not completely cover it.
Why It’s Important
Total solar eclipses provide a unique opportunity for scientists
to study the Sun and Earth from land, air and space, and allow
the public to engage in citizen science!
Total eclipse image taken March 20, 2015 in Svalbard,
Norway. Credit: S. Habbal, M. Druckmüller and P. Aniol
The sun's outer atmosphere (corona) and thin lower atmosphere
(chromosphere) can be seen streaming out from the covered disk
of the sun during a solar eclipse on March 20, 2015.
Credit: S. Habbal, M. Druckmüller and P. Aniol
On a typical day, the bright surface of the Sun, called
the photosphere, is the only part of the Sun we can see.
During a total solar eclipse, the photosphere is completely
blocked by the Moon, leaving the outer atmosphere of the Sun
(corona) and the thin lower atmosphere (chromosphere) visible.
Studying these regions of the Sun’s atmosphere can help scientists
understand solar radiation, why the corona is hotter than
the photosphere, and the process by which the Sun sends
a steady stream of material and radiation into space.
Scientists measure incoming solar radiation on Earth, also known
as insolation, to better understand Earth’s radiation budget –
the energy emitted, reflected and absorbed by Earth. Just as
clouds block sunlight and reduce insolation, the eclipse will block
sunlight, providing a great opportunity to study how increased
cloud cover can impact weather and climate.
(Learn more about insolation during the 2017 eclipse here.)
Citizen scientists can get involved in collecting data and participating
in the scientific process, too, through NASA’s Global Learning
and Observations to Benefit the Environment, or GLOBE, program.
During the eclipse, citizen scientists in the path of totality
and in partial eclipse areas can measure temperature and cloud cover
data and report it using the GLOBE Observer app to help further
the study of how eclipses affect Earth’s atmosphere.
You can learn more about the many ways scientists are using
the eclipse to improve their understanding of Earth, the Moon and the Sun here.
How to View It
Important! Do not look directly at the Sun or view the partial eclipse
without certified eclipse glasses or a solar filter. For more information
on safe eclipse viewing, visit the NASA Eclipse website.
When following proper safety guidelines, witnessing an eclipse is
an unparalleled experience. Many “eclipse chasers” have been known
to travel the world to see total eclipses.
The start time of the partial eclipse, when the edge of the Moon first
crosses in front of the disk of the Sun, will depend on your location.
You can click on your location in this interactive eclipse map to create
a pin, which will show you the start and end time for the eclipse
in Universal Time. (To convert from Universal Time to your local time,
subtract four hours for EDT, five hours for CDT, six hours for MDT,
or seven hours for PDT.) Clicking on your location pin will also
show you the percent of Sun that will be eclipsed in your area
if you’re outside the path of totality.
Aug 2017 eclipse map
This graphic shows the path of the Moon and Sun across
the US during the Aug. 21, 2017 eclipse. The gray line represents
the path of totality, while the Sun and Moon graphics flowing from
top to bottom represent the percent of coverage for areas outside
the path of totality. Image credit: NASA
If you are inside the approximately 70-mile-wide strip known as the path
of totality, where the shadow of the Moon, or umbra, will fall on Earth,
the total eclipse will be visible starting about an hour to 1.5 hours
after the partial eclipse begins.
Only when the eclipse is at totality – and the viewer is in
the path of totality – can eclipse glasses be removed. Look at the eclipse
for anywhere from a few seconds to more than 2.5 minutes
to see the Sun’s corona and chromosphere, as well as the darkened
near side of the Moon facing Earth. As before, your viewing location
during the eclipse will determine how long you can see the eclipse
in totality.
graphic showing when its safe to remove your eclipse glasses
if you are in the path of totality
Viewers should wear eclipse glasses or use a pinhole camera
for the entirety of the partial eclipse. Those in the path of totality
can remove their glasses only when the eclipse is in totality,
which may last from a few seconds to more than 2.5 minutes
depending on your location. Image credit: NASA
After totality ends, a partial eclipse will continue for an hour to 1.5 hours,
ending when the edge of the Moon moves off of the disk of the Sun.
Remember, wear eclipse glasses
or use a pinhole camera for the entirety of the partial eclipse.
Do not directly view the partial eclipse.
Animation of the pinhole camera project from NASA-JPL Education
Make a Pinhole Camera
Find out how to make your very own pinhole camera to safely
view the eclipse in action.
› Get started!
To get an idea of what the eclipse will look like from your location
and explore the positions of the Moon, Sun and Earth throughout
the eclipse, see this interactive simulation.
For more information about the start of the partial eclipse,
the start and duration of totality, and the percentage
of the Sun eclipsed outside the path of totality, find
your location on this interactive eclipse map.
NASA Television will host a live broadcast beginning
at 9 a.m. PDT on Aug. 21 showing the path of totality
and featuring views from agency research aircraft, high-altitude
balloons, satellites and specially-modified telescopes.
Find out how and where to watch, here.
Teach It
Use these standards-aligned lessons and related activities
to get your students excited about the eclipse and the science that will be
conducted during the eclipse.
Epic Eclipse – Students use the mathematical constant pi
to approximate the area of land covered by the Moon’s shadow during the eclipse.
Pinhole Camera – Learn how to make your very own pinhole camera
to safely see a solar eclipse in action from anywhere the eclipse is visible, partial or full!
Moon Phases - Students learn about the phases of the Moon by acting
them out. In 30 minutes, they will act out one complete, 30-day, Moon cycle.
NEW! Measuring Solar Energy During an Eclipse – Students use mobile
devices to measure the impact a solar eclipse has on the energy received at Earth’s surface.
NEW! Modeling the Earth-Moon System – Students learn about
scale models and distance by creating a classroom-size Earth-Moon system.
NASA GLOBE Observer – Students can become citizen scientists
and collect data for NASA’s GLOBE Program using this app available
for iOS and Android devices (eclipse update available starting August 18, 2017).
Explore More
NASA TV Eclipse 2017 broadcast info
NASA 2017 Eclipse website
NASA Eyes Eclipse 2017 Interactive
Interactive Eclipse Map
NASA Eclipse website (for info about other eclipses)
Eclipse Safety
American Astronomical Society website (for info on reputable vendors
of solar viewers and filters)
Earth’s Radiation Budget
TAGS: Eclipse, Solar Eclipse, Science, Pinhole Camera, K-12, Students, Educators
Lyle Tavernier
ABOUT THE AUTHOR
Lyle Tavernier, Educational Technology Specialist, NASA/JPL Edu
Lyle Tavernier is an educational technology specialist at NASA's Jet
Propulsion Laboratory. When he’s not busy working in the areas of distance
learning and instructional technology, you might find him running with his dog,
cooking or planning his next trip.
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