We have more exoplanets than friends
We finally found Earth-like planets. And now? According to Physics, now nothing.
The history of exoplanets (planets in other solar systems) is very recent. From a modus operandi that takes us back to the ideas of Christianity, for a long time we thought that only our Sun had planets. That’s because we couldn’t see anything orbiting neighboring stars. Then came the crazy 90s.
Ah, what a wonderful time: Romário winning the World Cup alone, the Internet entered our daily lives and Malhação (Brazilian soap opera reference) was filmed in a gym. In the midst of this information caos, in 1995, the first exoplanet is discovered.
Two distinguished Swiss astronomers, Michael Mayor and Didier Queloz, snooping around the 51 Pegasi-star, through the radial velocity technique — already explain the hell is this — became the first parents of a planet outside our system.
Using a powerful spectrograph, the pair was able to observe a slight color change in the star’s spectrum, always with the same time interval — the so-called Dopler Effect.
My first child will be called Kepler
So it’s real, there are planets out there! And with the advance of the search for exoplanets, we used simple mathematics to confirm that: all, or almost all stars in the Universe have planets, therefore, there are more planets than stars! How beautiful!
On March 7, 2009, NASA sent the Kepler Space Telescope into space, with a mission to find new exoplanets — using the transit method.
As we had not yet been able to directly observe an exoplanet — which from our point of view is very dark and the luminosity of its star makes it impossible to search — , the Kepler Space Telescope kept looking at potential candidates and waited for a shadow to orbit the star. If the shadow did this constantly and in the same amount of time, bingo! We had one more little cosmic friend.
Thus, the Kepler mission found 2,662 planets over its more than 9 years of service in space. As soon as our brave probe ran out of fuel and retired — Yes! In space, retirement is still a reality — The TESS mission was launched in 2018. Now the goal was to find nearby Earth-like planets.
In this crazy adventure, we encounter all kinds of planets: giant and gaseous like Jupiter, small and infernal like Mercury, frozen and desolate like Uranus and rocky and in the habitable zone of their systems like Earth.
Our new goal was to find a plan B that we would one day call home, a place that in the future, if things continue as they are, we would board some interstellar bus probably made by Elon Musk and we would depart for the new Earth! How many millions of horror movies have we seen with this theme? — Do not answer.
And we did it! We find planets nearly Earth-like — Kepler-438b and Gliese 667 Cc are favorites — in the habitable zone of their systems (not too close to the star to be an oven and not too far away to be frozen) and orbiting a slightly different Sun from ours, called the red dwarf — a smaller, more radioactively active star.
Cool, this could be the new humanity Condo. But according to current physics, there is no possibility of reaching these planets. In fact, not even our fourteenth generation would arrive with the space cars available today.
The simplest example is the solar system closest to ours, called the Alpha Centauri. This wonderful parish is a three-star system. In one of them, called Proxima Centauri, there is an exoplanet — discovered in 2016 using the radial velocity technique — that is in the habitable zone and could be a new Earth. Called Proxima Centauri b it is 4.37 light years away from you. Little right? Not!
Despite being the famous speed of light, 4.37 sounds cute doesn’t it? But bringing it to the traditional and renowned scale of kilometers: Proxima b is 40 trillion kilometers from Earth. For you to understand the drama, Pluto — which is a planet — and was visited by the New Horizons probe in 2015, is at a super ok distance of 7.5 billion kilometers. It took New Horizons 10 years to get to this special little place.
So, my dear Highlander, with all the propulsion technology we have today, it would take a human-made spaceship 81,000 years to reach Proxima b.
So, as cool as the quests to discover new planets are — and I adore and celebrate each new planet — there is no plan B. Earth is our home! And as much as they try to destroy her in different ways, we must fight to preserve this beautiful girl.
Lightsail, to infinity and beyond!
To finish for today, as the conversation is already way to boring, good news for at least one day we get to know an exoplanet, the so-called Lightsails. The Planet Society, a non-profit space exploration organization, came up with a sensational idea: to make small unmanned spaceships — just 32m² — in the shape of a kite, called Lightsail. They use an innovative propulsion system called the Solar Sail.
The Solar Candle basically uses a mirror that reflects sunlight and gains extreme and constant velocity with the pressure of radiation. These little wonders are already being tested in Earth’s low orbit. Lightsails would have the ability to travel at 240,000 km/h. — Our current record is 52,000 km/h achieved by the aforementioned New Horizons probe.
The idea is that once developed, this demonic kite can reach Proxima Centauri b in 20 or 30 years — from 81,000 to 30 is a life changer!
The thing though, is, we still don’t know how to stop these little babies, so, at this crazy speed, maybe the photo of our neighborhood will be a little blurry.