Why will detecting Earth-sized planets be much more difficult than finding Jupiter-sized planets around other stars?
It's not a question of "will be." We already have detected such planets. How do we detect any planets around distant stars? Why would it be easier to detect bigger ones than smaller ones?
It turns out that detecting planets around other stars is by the periodic dimming of the star, caused by the "eclipse" of the star by the planet.
A smaller planet will dim the star to a lesser extent, hence either the periodic dimming phenomenon is more difficult to observe, or the reduced dimming will be masked by the "noise", and hence more difficult to detect.
On the other hand, a larger sized planet will give a more definitive periodic dimming pattern, which makes it easier to detect.
Detecting Earth-sized planets is more difficult than finding Jupiter-sized planets due to several reasons. Here's an explanation of why it's more challenging:
1. Size and Mass: Earth-sized planets are significantly smaller and less massive than Jupiter-sized planets. This results in a much lower gravitational pull, making it harder to observe their effects on the star they orbit.
2. Transit Method: One of the common techniques to detect exoplanets is the transit method. It involves measuring the slight dimming of a star's light when a planet passes in front of it. However, an Earth-sized planet passing in front of its star causes a much smaller drop in brightness compared to a Jupiter-sized planet. This tiny signal is challenging to distinguish from other sources of noise or variability from the star.
3. Atmospheric Composition: Detecting Earth-sized planets also involves studying their atmospheres. Jupiter-sized planets have more massive atmospheres, making it easier to observe their chemical composition and search for signs of life. Earth-sized planets have much thinner atmospheres, making it more difficult to detect and analyze any potential biomarkers.
4. Distance from the Star: Earth-sized planets are more likely to be located closer to their star, resulting in shorter orbital periods. This means that they complete their orbit quicker, making it necessary to observe multiple transits to confirm their existence and determine their characteristics accurately.
5. Instrumental Limitations: Current telescope technology and instruments have limitations when it comes to detecting Earth-sized planets. The precision and sensitivity required to detect such tiny signals are still a challenge, although advancements are being made.
Despite these difficulties, significant progress has been made in recent years, and the discovery of Earth-sized exoplanets is becoming more common. Improvements in technology, such as the development of more precise telescopes and innovative observational techniques, will help in the future hunt for Earth-like planets.