"It was an ordinary day for Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, (and don't forget Pluto, the dwarf planet). The planets were circling the Sun, staring into space, until suddenly they spot something else in their Solar System. What could it be? Who could it be? The planets have no idea but they're circling to find out. Whatever it is that something is most definitely, absolutely, without a doubt NOT a planet. So begins an out-of-this-world pen pal exchange between the planets and an exoplanet: Dear Exoplanet, We are excited to have you in the galaxy! XO, Planets Dear Planets, It is nice to hear from you! But what is an exoplanet? Does it mean "excellent planet"? XO, Exoplanet Paired with vibrant illustrations from Jorge Lacera, this STEM-friendly story, told mainly through letters, reminds readers what happens when we consider another person's point of view." -- Provided by publisher.