The total solar eclipse of August 21, 2017, will track
eastward across the US starting around 9 a.m. PDT.
NASA will fly “eclipse jets” to make totality — when
the moon blocks out the sun — last nearly three times as
The jets will use telescopes to study the
sun’s corona, or outer
The total solar eclipse of August 21, 2017, will be the first in
nearly 100 years to cut across the entire continental United
For most Americans in the path of the eclipse’s umbra — where the
moon totally blocks out the sun and casts its darkest shadow —
the strange phenomenon of will last about 2 minutes 30 seconds as the eclipse
tracks from West to East.
The first near
Madras, Oregon, around 9:06 a.m. PDT. The last seen in the
US will end around Columbia, South Carolina, around 4:06 p.m.
But NASA-funded scientists at the Southwest Research
Institute (SwRI) in Boulder, Colorado have a clever plan to beat
any potential cloudy weather conditions and extend the duration
of totality to about 7 minutes — nearly triple the time seen
on the ground.
The team, led by space scientist , will fly inside two of
NASA’s high-speed “eclipse jets” and chase the shadow as it moves
The expedition isn’t a pleasure cruise — it’s one of that NASA has funded in advance of the
total solar eclipse.
How to chase a total solar eclipse
Each WB-57F research aircraft (as eclipse jets are officially
called) will take off from NASA’s Johnson Space Center near
Once they reach about 50,000 feet, they’ll make their way over
Missouri, Illinois, and Tennessee as they chase the umbra.
Each aircraft has a suite of sensitive instruments mounted onto
its nose. One is a pair of telescopes, which SwRI researchers
will point at the sun to record what may be the clearest-ever
photos of the sun’s corona, or outer atmosphere.
The corona is millions of degrees hotter than the surface of the
sun, which is about 10,000 degrees Fahrenheit, and scientists
don’t fully understand why.
Part of the challenge is that the corona is difficult to study.
It’s dramatically dimmer than our star’s main disk, and
instruments in space like NASA’ Solar Dynamics Observatory can’t
see it well in important wavelengths of light, such as green
(which is best for studying the corona’s structure).
But from Earth, the moon happens to be almost precisely
the size of the sun’s disk. When the moon passes in front of
the sun, it will reveal the wispy corona extending millions
of miles from the solar surface deep into space.
Caspi and his team will mainly be looking for a rarely seen,
high-speed phenomenon called Alfvén waves. Such waves were
and may be the key to shuttling heat from the sun’s
surface to its corona.
“Extending the observing time and going to very high altitude
might allow us to see a few events or track waves that would be
essentially invisible in just two minutes of observations from
the ground,” Caspi said in .
In addition to studying Alfvén waves, researchers plan to point
the telescopes on each jet toward the planet Mercury.
They’ll take those observations before and after totality, when
the sky is still mostly dark and the telescopes can make a map of
Mercury’s surface temperatures.
According to NASA, those measurements could help reveal the
planet’s soil composition and “give scientists insight into how
Mercury and other rocky planets may have formed.”