Kepler also functions as a space observatory, measuring 4.7 meters in length, 2.7 meters in width, and weighing over 1 ton, with the purpose of “hunting” for Earth-like planets beyond our Solar System using a telescope with a diameter of 0.95 meters.
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Illustrative image of the planet Kepler-452b provided by NASA. REUTERS/NASA/Ames/JPL-Caltech/T. Pyle
Kepler-452b is the latest discovery of the Kepler spacecraft, announced by scientists on July 23, 2015. Hidden behind this name is a planet that shares many “points of similarity” with our Earth. Le Monde, a French newspaper, published an explanatory article in the form of questions about the mysteries surrounding this planet.
What is an exoplanet?
An exoplanet is a planet that orbits a star other than the Sun (outside our Solar System). The first exoplanet was discovered in 1995 – the planet 51 Pegasi b. Currently, scientists estimate there are about 1,030 “official” exoplanets. However, the Kepler satellite from the U.S. has identified nearly 5,000 exoplanet “candidates,” requiring specific criteria for selection. Jean Schneider, an astronomer working at the Meudon Observatory on the outskirts of Paris, manages a website with a comprehensive collection of information about these planets.
What is the size of Kepler-452b?
Kepler-452b has a radius 1.6 times larger than Earth’s, equivalent to 10,194 km. Therefore, this exoplanet is four times larger than Earth. Kepler-452b orbits around its star (“Sun”) in 385 days, more than 20 days longer than Earth’s orbit around the Sun.
Another interesting fact is that Kepler-452b’s star is also a G-type star, similar to our Sun. In contrast, stars of planets “relatives” to Earth are smaller, cooler, and less luminous. These conditions present obstacles to the existence of life on those planets.
What is the composition of Kepler-452b?
Currently, scientists still do not know the composition of this planet. According to NASA, there’s a 50% chance that the surface of Kepler-452b could be rough like Earth’s. However, the Kepler satellite has not yet determined the weight of this exoplanet. Nonetheless, scientists believe it could be five times heavier than Earth. If it has a rugged surface, a planet of this size or weight could potentially have active volcanoes. Ultimately, identifying the mass could provide insight into whether this planet has an atmosphere.
How is this planet “seen”?
The Kepler space telescope has its own method for detecting exoplanets. This was the mission when NASA launched the Kepler satellite in 2009. It’s known as the “transit method.” The Kepler satellite records changes in the brightness of the star (“Sun”) being observed as a planet passes in front of it. Analyzing the dark patches on the star’s surface allows scientists to determine the exoplanet’s size and distance from the star. It also helps determine whether the planet is within the “habitable zone.” However, this method doesn’t allow for determining the planet’s mass.
What is the “habitable zone”?
The “habitable zone” (also known as the “Goldilocks zone”) refers to the region around a star where liquid water on a planet’s surface could exist – a necessary condition for the development of life. This is the case with Earth. For instance, Mercury is too close to the Sun for water to exist in any form, while Mars is too far from the Sun, resulting in water existing only as ice.
Kepler-452b isn’t the only exoplanet located within the habitable zone; it’s currently the only planet that’s close in size to our Earth and orbits a star similar to the Sun.
Is the “habitable zone” the only factor for the emergence of life?
No. The emergence of life depends on multiple factors. Just observing our own planet provides insight into the fundamental factors. Apart from being in the “habitable zone” of our Solar System, Earth has a protective atmosphere that filters out harmful solar radiation, such as ultraviolet rays, and retains heat through the greenhouse effect. Earth also has a magnetic field that diverts deadly charged particles from the solar wind. These particles interact with the upper atmospheric layer, creating the phenomenon of auroras at the North and South Poles.
Can exoplanet Kepler-452b provide information about Earth’s future?
Because Kepler-452b is 1.5 billion years older than Earth and if it can be confirmed that this exoplanet shares many similarities with Earth, Kepler-452b might provide insights into what will happen to our planet in over a billion years, when the Sun becomes hotter, potentially causing water on Earth to evaporate.
What is the distance between Kepler-452b and Earth?
Kepler-452b is located 1,400 light-years away from Earth. It is situated in the Cygnus constellation. One light-year is equivalent to 9.461 trillion kilometers. The speed of light is about 300,000 km/second. Therefore, Kepler-452b is more than 13 million trillion kilometers away from Earth.
How long would it take to travel to Kepler-452b?
The New Horizons spacecraft recently captured images of Pluto, the farthest planet in our Solar System, which holds the record for speed at about 60,000 km/h. Assuming a spacecraft carrying humans could travel at that speed, it might take about 25 million years to reach Kepler-452b. This would indeed be an extraordinarily long journey!
Is it possible to send a message to the hypothetical inhabitants of Kepler-452b?
Assuming there is life on this planet and similar technologies to those on Earth, it would likely take around 1,400 years for a light-speed message to reach Kepler-452b. To receive a response, a similar amount of time would be needed. As a result, we would need to be patient for approximately 2,800 years to exchange information.