he search for exoplanets is a relatively
new and exciting aspect of study,
and finding Earth 2.0 is a goal that
astronomers hope to achieve by
using innovative methods of detection. Based
on Einstein’s theory of general relativity which
predicted that the most massive objects in
universe can warp the space around them and
can bend light, a process known as gravitational
lensing, it is possible to concentrate distant light to
allow for a closer look.
This century-old theory has led to the
development of the solar gravity lens (SGL)
method of exoplanet detection, courtesy of
scientists from NASA’s Jet Propulsion Laboratory
and The Aerospace Corporation. This two-year
study was made possible when Aerospace was
awarded a $130,000 contract from JPL as part of
the NASA Innovative Advanced Concepts (NIAC)
Phase II program.A swarm of telescopes placed billions of kilometres away will
be able to reveal a universe full of exoplanets
“SGL requires placement of an array of detectors
that observe the light from exoplanets once they
arrive at a distance approximately 50 billion miles
[80.5 billion kilometres] or 550 astronomical
units (AU) from Earth,” says Tom Heinsheimer,
Aerospace’s technical co-lead for SGL. “To get to
that solar gravity line the swarm of spacecraft
will need to use a solar sail to fly out of the
Solar System at a velocity of over 75 miles [121
kilometres] per second.” One AU is the Earth-Sun
distance, meaning the distance of this focal ‘ring’
would be three light days away.
By placing a system of telescopes over 80
billion kilometres (50 billion miles) from Earth the
SGL will provide an outstanding magnification
of 100 billion. This level of magnification will
reveal details as small as 10-kilometres (six-miles)
across – the equivalent of spotting New York City
on an exoplanet. This grand scale of telescopes
would undeniably tackle exoplanet detection in apioneering fashion, but there are problems
to tackle before doing so – the main one being
having to send a swarm of satellites such an
enormous distance from Earth.
When considering the farthest human-made
object, NASA’s Voyager 1 currently holds that record
at 145 AU from Earth – and that has taken over
40 years! This long time span is only because the
spacecraft was restricted by the technologies of its
time. With the new proposed propulsion and light-
sail concept the cluster of small telescopes will take
roughly 30 years to get to a distance of 550 AU.
The navigation and propulsion will require
some form of artificial intelligence, as technologies
will need to keep the spacecraft flying in a
1.6-kilometre- (one-mile) wide line that will contain
the light from the exoplanet. As this round trip of
communication with Earth would take six days it
is imperative that this swarm can adapt and learn
from experience.Communication of indication
The satellites will need to
communicate with ground control
on Earth to pass on any data. To
beam data between the two will
take three days due to the finite
speed of light.The main player
The Sun’s gravity is so vast that it
can bend the light of stars around its
periphery, similar to how a lens in a
pairofglassesworks.Thiswillallow
the satellites to provide 100-billion
optical magnification.FUTURE TECH Solar gravity lens
T