The US space agency, NASA, has confirmed that the number of confirmed exoplanets has reached 5,005, representing a 30-year journey of discoveries led by telescopes.
“The planets include small, rocky Earth-like worlds and gas giants many times larger than Jupiter, in very close orbits around their stars,” the agency said. Plus super-terrestrial planets, which are rocky worlds larger than our own, and small Neptunes, smaller versions of Neptune in our system. In addition to the mixture of planets orbiting two stars at the same time and planets orbiting the collapsed remains of dead stars.”
“It’s not just a number, every planet discovered is a whole new world,” said Jesse Christiansen, lead archival science and research scientist at the NASA Exoplanet Science Institute at Caltech. We are excited to get to know each one up close, because we don’t know anything about composition.”
She added: “We are certain that our galaxy contains hundreds of billions of these planets, and the drums of discovery began to beat in 1995 with strange new worlds revolving around a star that is more strange in its behavior to scientists. Bursts of scorching radiation in milliseconds. Measuring subtle changes in the timing of the pulsations allowed the scientists to detect planets in orbit around the pulsar.”
“Finding only three planets around this rotating star has opened the doors to discovery, which was spotted 30 years ago for the first confirmed planets outside our system,” said Alexander Walchzan, lead author of the study.
Scientists have shown how to find other worlds, as the picture of the planets will not always be very bright. The first planet discovered around a sun-like star, in 1995, turned out to be hot Jupiter: a gas giant about half the mass of our Jupiter in a very close four-day orbit around its star our galaxy.