How can scientist tell if a planet exists near a distant star?
Astronomers can detect the dim companion by observing the effects of its gravity. The dim star's gravity causes the bright star to wobble. Astronomers use this same method to detect planets around other stars
You can observe to see if a star appears to wobble over time, due to the gravitational pull of an orbiting planet. You can also obseve the light being emmited from the star. The intensity of light from a star can increase (not decrease) when a planet passes in front of the star relative to the observer. This is because the planet's gravity acts like a lens.
There are four ways in which an exoplanet can be detected. Transit method- a planet passes in front of the star making it detectable Astrometry- the center of mass near a star is shifted by a planet making the star wobble Doppler shift- the wave length of the radiation coming from the star will shift if there is a planet present Radial lensing- when looking at pictures of the distant star there will be a…
Right now you don't, because it would take so long that you would be dead long before getting anywhere near a planet outside out solar system. It is highly unlikely humans will ever be able to travel to any planet other than our neighbor Mars (we could get to several others in our solar system in a reasonable time but would die if we attempted to land).