Exoplanets: The search for Earth's sister planet
Exoplanetary scientist Jonathan Fraine told us how the search for a second Earth could explain our own beginning.
For 55 years now, scientists have been foraging in space for signs of life. Instead of simply asking, “are we alone?”, scientists now want to know how unique Mother Earth really is.
By studying exoplanets, which orbit stars outside of the solar system, astronomers believe that they can piece together the origin of Earth and mankind.
"Exoplanets are a way to put context to our own creation," Jonathan Fraine said, an astronomer specializing in the study of exoplanets, "they put context to how the solar system formed, and that’s how we came about."
The ‘golden egg’ of exoplanet science is to find an Earth-like planet with a 350-day orbit around a star that resembles the vitality of the Sun, dubbed “Earth-2."
What many are interested in knowing, however, is whether human travel to these planets is possible. Technology has yet to reach the standards of George Lucas’ Star Wars universe, where spaceships soar faster than the speed of light.
By studying inaccessible planets and how they are formed, predictions about finding life elsewhere become possible.
None of the planets detected thus far are habitable, but by analyzing what they are made of and how they were formed, scientists hope to find clues about the formation of the solar system to further understand how life on Earth came about in the first place.
Exoplanet science meshes astrophysics and planetary science. Astrophysics asks questions about objects in space, like how stars and planets are formed. Planetary science looks at the properties of these objects, such as their atmospheric conditions.
For almost 100 years, planetary science focused on Earth’s backyard, the solar system. In the past 20 years, scientists found 3,000 potential exoplanets and 1,800 confirmed exoplanets.
“We look at the planets in our solar system and try to find echoes of those planets throughout the galaxy,” Fraine said, “in fact, we’re finding things in huge numbers that look nothing like what we see in our solar system."
Since exploration has widened from humanity’s backyard to the galaxy, scientists have had to adopt new techniques to detect foreign worlds.
The National Aeronautics and Space Administration (NASA)’s Kepler Mission is specifically designed to survey the Milky Way for Earth-like planets within the ‘goldilocks’ zone — the distance from a star that is neither too hot nor too cold to sustain liquid water.
The Kepler telescope, which orbits the Sun, examines a slice of the star field for the length of its mission, lasting three and a half years or more. Every few hours, this telescope records data on the brightness of more than 100,000 stars, simultaneously, for the life of the mission.
"If you hold your hand out as far as you can, and tuck your fingers in, that’s roughly 10 degrees on the sky,” Fraine said, “that’s about the same as Kepler’s scope. We’ve found 4,000 planets in the size of the palm of your hand. We have 36 more of these fields to look at.”
Kepler uses changes in the light emitted by a star in order to tell if a planet is orbiting it. When a planet passes in front of a star, it blocks some of its light, like an eclipse. By measuring the difference in the reduced brightness, astronomers can determine the size of the planet. The bigger the planet, the larger the drop in light.
As the planet passes behind the star, light reflected onto the planet disappears, resulting in another dip in brightness. Using this information, the difference in brightness, the exoplanet’s temperature can be deduced.
Direct imaging, looking directly at the star through a telescope and trying to spot any planets surrounding it, seems far simpler. Yet, it has only worked a handful of times because the stars outshine the orbiting planets, making it near impossible to detect them.
“Imagine the brightest lighthouse on the face of the planet,” Fraine explained, “and you’re trying to stare at it and find the firefly sitting next to it. If we’re here in Beirut, the lighthouse and firefly are in Moscow."
The latest technology uses direct imaging with infrared, which is where heat comes from. This allows scientists to sift through the overwhelming starlight and makes it easier to detect exoplanets.
“Before Kepler, we weren’t finding anything remotely Earth-like. Now almost all the planets we’ve found are around Earth’s orbital period and size, but they’re much closer to their star than we are to the Sun," the exoplanet scientist explained.
With consistent advances in technology, astronomers are hopeful to find “Earth-2.” Fraine believes science is a few years and a few thousand observations away from getting closer to Earth’s sought after twin planet.
Lebanon lacks the technological sophistication, resources, and concerted scientific collaboration required to advance its own study of astronomy.
Manoug Manougian, an Armenian professor at Haigazian University, famously constructed a rocket that launched into Earth’s upper atmosphere in the 1960s.
“We tried once to make a center of astronomy, but no one was willing to invest,” Dr. Mounib Eid, a Physics professor at the American University of Beirut, said, “but there is also no teamwork in Lebanon, not like in Europe.”
With rising concern over global warming and the Islamic State on our borders, many feel that astronomy is not a worthwhile pursuit.
“This country has so many problems, so people think astronomy isn’t important,” Eid said, “but knowing that it is so difficult to find a planet like our Earth gives us a really big responsibility to save this planet, because it’s unique.”