Historic solar eclipse could

prove our star is hundreds

of miles larger



The sun could be much bigger than we think, Nasa scientists have claimed. Pictured is sun with active regions combined to look something like a jack-o-lantern’s face
The sun could be much bigger than we think, Nasa scientists 
have claimed. Pictured is sun with active regions combined 
to look something like a jack-o-lantern’s face

  • Researchers that study solar eclipses believe the sun is 
  • larger than we think
  • Modelling suggests sun could be a few hundred miles
  •  larger than believed
  • This year's solar eclipse, which falls on August 21, 
  • could prove their predictions 
The sun could be much bigger than we think, Nasa scientists
 have claimed.Researchers studying the shadows cast during 
a solar eclipse believe they have found evidence suggesting
 our star has a far larger radius than previously believed.
And this year's historic solar eclipse, which falls on August 21,
 could prove that we've been underestimating the size of the sun
 for almost 200 years, the researchers said.

Researchers believe they have found evidence suggesting our star has a far larger radius than previously believed (pictured is a stock image of a solar eclipse)
Researchers believe they have found evidence suggesting our
 star has a far larger radius than previously believed 
(pictured is a stock image of a solar eclipse)
In 1891, a German astronomer known as Arthur Auwers 
was the first to estimate the size of the sun.
Based on the star's photosphere, the body of the sun whose
 wavelengths are visible to the naked eye, he calculated that 
the sun had a radius of 432,470 miles (696,000km).
This benchmark figure was widely used until 2015, when 
the International Astronomical Union updated this figure to
 432,280 miles (695,700km) based on data from 
solar-observing satellites.
But now a growing number of scientists have claimed that 
both of these estimates are too small.
Xavier Jubier, a researcher from Antony in France who
 creates detailed models of solar and lunar eclipses for
 Google Maps, said his observations suggest the sun
 is bigger than we think.
As part of his work, he predicts where the shadow 
created by a solar eclipse will fall on Earth.
He noticed that something was wrong with the sun's
 measurements while he was comparing his previous
 eclipse predictions with photos taken during historical
 solar eclipses.
Mr Jubier was able to match the location of the photographs
 to that predicted by his models - but only if he scaled by
 the sun's radius by a few hundred kilometres. 
'For me, something was wrong somewhere, but that's 
all I could say,' Mr Jubier told Space.com.
And Ernie Wright, a researcher from Nasa's Goddard Space
 Flight Center in Greenbelt, Maryland, who also creates
 precise models of solar eclipses, found himself in a 
similar dilemma to Mr Jubier.
He too found that he could only make his models match 
reality if he increased the size of the sun in his calculations. 
The sun could be much bigger than we think, Nasa scientists have claimed. Pictured is sun with active regions combined to look something like a jack-o-lantern’s face
The sun could be much bigger than we think, Nasa scientists 
have claimed. Pictured is sun with active regions combined 
to look something like a jack-o-lantern’s face
The researchers hope this year's upcoming eclipse, which
 will likely be the most-watched solar eclipse in history, will 
provide a chance for scientists to verify the size of the sun.
A group of scientists plan to study the eclipses' 'contact time', 
the time when the moon will cover the sun for a given location,
to help them figure out the star's size.
Normally, researchers use the radius of the sun to predict 
the length of contact time during an eclipse - and it is believed
 that these calculations could be reversed to help
 scientists predict the size of the sun. 

'If we can measure contact times accurately, everything else
 being the same, the only thing that can change is the solar
radius,' Luca Quaglia, a physicist and eclipse researcher
 from the American Astronomical Society, told Space.com.
'We can actually compute the solar radius that way.'
The team plan to to use 'flash spectrum' photography, 
which uses a textured grating over a camera to split
 incoming wavelengths of light.
By doing this, they can easily determine the precise moment 
contact time is initiated during the eclipse, they said.
And by combining this information with accurate time stamps, 
they will be able to make an accurate prediction of the
 size of the sun, they claimed.
'The more observations we have the better even if they 
are not providing the kind of quality we expected
 to get,' Mr Jubier said.
'Time will tell what we can make of all this.'