The 7 alien planets orbiting TRAPPIST-1 are like peas in a pod

Refining the Transit-timing and Photometric Analysis of TRAPPIST-1: Masses, Radii, Densities, Dynamics, and Ephemerides,, “Abstract We have collected transit times for the TRAPPIST-1 system with the Spitzer Space Telescope over four years. We add to these ground-based, HST, and K2 transit-time measurements, and revisit an N-body dynamical analysis of the seven-planet system using our complete set of times from which we refine the mass ratios of the planets to the star..."

A very intriguing multiple planet system in this article. My observation. The abstract indicates TRAPPIST-1 system is stable on 10 million year *timescales* but the red dwarf host star is considered some 7 billion or more years old. MS BING search reports “Scientists wrote in an August 2017 study that TRAPPIST-1 is between 5.4 and 9.8 billion years old. This is up to twice as old as our own solar system, which formed some 4.5 billion years ago. Throughout 2017, scientists worked on creating sophisticated computer models to simulate the planets based on available information.” Another interesting note from the report, “The seven TRAPPIST-1 planets possess similar densities—the values differ by no more than 3%. This makes the system quite different from our own. The difference in density between the TRAPPIST-1 planets and Earth and Venus may seem small—about 8% – but it is significant on a planetary scale.”, ref

Currently this site shows 722 confirmed host stars with multiple planet systems (exoplanets),, and 738 at this site,

Studying these multiple planet systems and comparing our own, demonstrates how unique and different our solar system is as well as Earth, teeming with life here vs. at these stars with multiple exoplanets orbiting them.
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