{"id":14642,"date":"2025-06-03T07:00:00","date_gmt":"2025-06-03T05:00:00","guid":{"rendered":"https:\/\/www.telescoop.nl\/?p=14642"},"modified":"2025-11-27T19:30:36","modified_gmt":"2025-11-27T18:30:36","slug":"how-many-planets-are-there-actually","status":"publish","type":"post","link":"https:\/\/staging.telescoop.nl\/en\/hoeveel-planeten-zijn-er-eigenlijk\/","title":{"rendered":"How many planets are there actually?"},"content":{"rendered":"<p class=\"wp-block-paragraph\"><strong>How many planets are there?<\/strong> That question seems simple, but the answer depends greatly on how you define \u2018planet. Do you say eight, nine or thousands? The answer is both scientifically and culturally interesting, and the discussion about Pluto plays a big part in that. In this blog, we explain how many planets there are in our solar system, which objects are no longer included, and how many worlds have now been discovered outside our solar system.<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-8d39b2df wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/staging.telescoop.nl\/wp-content\/uploads\/2025\/06\/Planets2013_nl.svg\" alt=\"how many planets are there actually\" class=\"wp-image-14643\" title=\"\"><figcaption class=\"wp-element-caption\">By Minionguyjpro - This file is derived from: Planets2013.svg:, CC BY-SA 4.0, https:\/\/commons.wikimedia.org\/w\/index.php?curid=115481472<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n<h3 class=\"wp-block-heading\">What is a planet according to science (official definition)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">According to the <a href=\"https:\/\/www.iau.org\/\" target=\"_blank\" rel=\"noopener\">International Astronomical Union (IAU)<\/a> there are three conditions an object must meet to be a planet:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>It orbits a star (like our sun).<\/li>\n\n\n\n<li>It has enough mass to have a round shape due to gravity.<\/li>\n\n\n\n<li>It wiped its orbit around the sun clean of other objects.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Based on that definition, our solar system counts <strong>eight official planets<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Mercury<\/li>\n\n\n\n<li>Venus<\/li>\n\n\n\n<li>Earth<\/li>\n\n\n\n<li>Mars<\/li>\n\n\n\n<li>Jupiter<\/li>\n\n\n\n<li>Saturn<\/li>\n\n\n\n<li>Uranus<\/li>\n\n\n\n<li>Neptune<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">What about Pluto?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Until 2006, Pluto was considered the ninth planet. It meets the first two conditions, but <strong>not to the third<\/strong>: Pluto shares its orbit with many other objects in the Kuiper Belt: a ring of icy objects at the edge of the solar system. Therefore, Pluto was renamed <strong>dwarf planet<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Besides Pluto, there are four other objects officially recognized as dwarf planets:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Eris<\/li>\n\n\n\n<li>Haumea<\/li>\n\n\n\n<li>Makemake<\/li>\n\n\n\n<li>Ceres (which is in the asteroid belt)<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Although dwarf planets are no longer official planets, they are still important to our understanding of the formation of the solar system.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How many planets are there outside our solar system?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In recent decades, we have begun to look far beyond our own solar system. Thanks to telescopes such as <strong>Kepler<\/strong>, <strong>TESS<\/strong> and <strong>James Webb<\/strong> are more than <strong>5,000 exoplanets<\/strong> discovered. These planets orbit other stars in our Milky Way.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Some exoplanets resemble Earth, others are gas giants like Jupiter, and some fall into categories we are not familiar with here, such as \u2018super-Earths\u2019 or \u2018hot Jupiters.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\ud83d\udd17 Find out more about recent discoveries in our blog on <a>the James Webb Space Telescope<\/a><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How many are there in total?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Astronomers estimate that our Milky Way alone is <strong>hundreds of billions of planets<\/strong> contains. Most have not yet been discovered, but their existence is inferred through:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Gravitational influences on other celestial bodies<\/em>, t<em>ransit photometry<\/em> (light attenuation when passing in front of a star) and r<em>adial velocity measurements<\/em><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What are dwarf planets and asteroids?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In addition to the eight planets and five official dwarf planets, there are thousands of smaller objects, such as <strong>asteroids<\/strong> (asteroids) and <strong>TNOs<\/strong> (Trans-Neptunian Objects).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Some of these objects are nearly circular and might have received planetary status under a more flexible definition. The discussion about <strong>Pluto and the planet definition<\/strong> thus remains topical, especially in educational circles.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What can you see for yourself with a telescope?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">You can't observe all the planets with a telescope, but you can observe some of them:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Jupiter<\/strong> and its moons are visible even with a small telescope.<\/li>\n\n\n\n<li><strong>Saturn<\/strong> shows its rings as early as 60x magnification.<\/li>\n\n\n\n<li><strong>Mars<\/strong> is red and recognizable, especially around opposition (opposition is when a planet is closest to Earth)<\/li>\n\n\n\n<li><strong>Venus<\/strong> exhibits phases, just like the moon.<\/li>\n\n\n\n<li><strong>Mercury<\/strong> is tricky, but sometimes visible at sunrise or sunset.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\ud83d\udd17 Want to know more? Check out our <a href=\"https:\/\/staging.telescoop.nl\/en\/how-to-choose-a-telescope\/\" data-type=\"post\" data-id=\"5155\">guide to planetary observation<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Pluto is too small and too dim to see with amateur equipment unfortunately... so it falls just outside the boat again.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Conclusion: how many planets are there?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The question \u201chow many planets are there actually?\u201d has several correct answers, depending on your definition:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Category<\/th><th>Number<\/th><\/tr><\/thead><tbody><tr><td>Official planets<\/td><td>8<\/td><\/tr><tr><td>Recognized dwarf planets<\/td><td>5<\/td><\/tr><tr><td>Confirmed exoplanets<\/td><td>5.000+<\/td><\/tr><tr><td>Expected exoplanets<\/td><td>Hundreds of billions(!)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Clearly, our understanding of planets is dynamic. As we develop new technologies and look further into the universe, these numbers will continue to grow.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Want to know more about which telescope you need to see planets? Read our <a class=\"\" href=\"https:\/\/staging.telescoop.nl\/en\/the-best-telescope-for-beginners\/\">selection guide for beginners<\/a> or <a href=\"https:\/\/staging.telescoop.nl\/en\/planets-in-our-solar-system\/\" data-type=\"post\" data-id=\"1221\">read a comprehensive blog post about planets in our solar system including photos here.<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Hoeveel planeten zijn er? Die vraag lijkt eenvoudig, maar het antwoord hangt sterk af van hoe je &#8216;planeet&#8217; definieert. Zeg je acht, negen of duizenden? Het antwoord is zowel wetenschappelijk als cultureel interessant en de discussie over Pluto speelt daar een grote rol in. In deze blog leggen we uit hoeveel planeten er zijn in [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":14643,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[168,2985],"tags":[],"class_list":["post-14642","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-astronomie-kenniscentrum","category-astronomie-101"],"acf":[],"jetpack_featured_media_url":"https:\/\/staging.telescoop.nl\/wp-content\/uploads\/2025\/06\/Planets2013_nl.svg","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":14648,"url":"https:\/\/staging.telescoop.nl\/en\/is-de-maan-een-planeet\/","url_meta":{"origin":14642,"position":0},"title":"Is the Moon a planet?","author":"Info telescoop","date":"12-06-2025","format":false,"excerpt":"De vraag \u201cIs de Maan een planeet?\u201d wordt verrassend vaak gesteld. Zeker door kinderen, maar ook door volwassenen die net beginnen met sterrenkunde. En het is begrijpelijk: de Maan is rond, heeft een oppervlak vol kraters, en draait aan de hemel zoals een planeet dat zou doen. Toch is het\u2026","rel":"","context":"In &quot;Astronomie Kenniscentrum&quot;","block_context":{"text":"Astronomie Kenniscentrum","link":"https:\/\/staging.telescoop.nl\/en\/astronomie-kenniscentrum\/astronomie-kenniscentrum\/"},"img":{"alt_text":"is de maan een planeet","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/02\/the-moon-with-Vespera-Pro-scaled-1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/02\/the-moon-with-Vespera-Pro-scaled-1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/02\/the-moon-with-Vespera-Pro-scaled-1.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/02\/the-moon-with-Vespera-Pro-scaled-1.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/02\/the-moon-with-Vespera-Pro-scaled-1.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/02\/the-moon-with-Vespera-Pro-scaled-1.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":5162,"url":"https:\/\/staging.telescoop.nl\/en\/planeten-waarvan-je-niet-gelooft-dat-ze-bestaan-volume-2-corot-7b\/","url_meta":{"origin":14642,"position":1},"title":"Planets you don't believe exist: Volume 2 - COROT-7b","author":"admin","date":"22-11-2024","format":false,"excerpt":"Als je dacht dat HD 189733 b al onvoorstelbaar was met zijn glasregens en onstuimige weerpatronen, dan zal COROT-7b je zeker niet teleurstellen. Deze exoplaneet is misschien wel een van de meest bizarre werelden die we tot nu toe hebben ontdekt. COROT-7b bevindt zich op slechts 480 lichtjaar van ons\u2026","rel":"","context":"In &quot;Astronomie 101&quot;","block_context":{"text":"Astronomie 101","link":"https:\/\/staging.telescoop.nl\/en\/astronomie-kenniscentrum\/astronomie-101\/"},"img":{"alt_text":"COROT-7B","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/COROT-7B-scaled-1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/COROT-7B-scaled-1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/COROT-7B-scaled-1.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/COROT-7B-scaled-1.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/COROT-7B-scaled-1.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/COROT-7B-scaled-1.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":1221,"url":"https:\/\/staging.telescoop.nl\/en\/planeten-in-ons-zonnestelsel\/","url_meta":{"origin":14642,"position":2},"title":"Planets in our solar system","author":"admin","date":"29-05-2024","format":false,"excerpt":"Ons zonnestelsel is een mooie en bijzondere plek, bestaande uit de zon en de acht planeten die daaromheen draaien. Elk van deze planeten heeft unieke eigenschappen en biedt talloze interessante feiten om te ontdekken. In deze blogpost zullen we de planeten in volgorde van hun afstand tot de zon verkennen,\u2026","rel":"","context":"In &quot;Astronomie 101&quot;","block_context":{"text":"Astronomie 101","link":"https:\/\/staging.telescoop.nl\/en\/astronomie-kenniscentrum\/astronomie-101\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/05\/500px-Neptune_Voyager2_color_calibrated.webp?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":14601,"url":"https:\/\/staging.telescoop.nl\/en\/waarom-jupiter-krimpt\/","url_meta":{"origin":14642,"position":3},"title":"Why Jupiter is shrinking","author":"Info telescoop","date":"02-06-2025","format":false,"excerpt":"Het klinkt bijna als sciencefiction, maar het is echt waar: Jupiter krimpt. De grootste planeet van ons zonnestelsel blijkt niet altijd zo geweest te zijn. 4,5 miljard jaar geleden was hij zelfs twee keer zo groot. En nog steeds is hij aan het samentrekken \u2014 langzaam maar gestaag. En dat\u2026","rel":"","context":"In &quot;Astronomie Kenniscentrum&quot;","block_context":{"text":"Astronomie Kenniscentrum","link":"https:\/\/staging.telescoop.nl\/en\/astronomie-kenniscentrum\/astronomie-kenniscentrum\/"},"img":{"alt_text":"jupiter krimpt","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/06\/57835cc6-9d29-469c-86dc-aba09546fa39.webp?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/06\/57835cc6-9d29-469c-86dc-aba09546fa39.webp?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/06\/57835cc6-9d29-469c-86dc-aba09546fa39.webp?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/06\/57835cc6-9d29-469c-86dc-aba09546fa39.webp?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2025\/06\/57835cc6-9d29-469c-86dc-aba09546fa39.webp?resize=1050%2C600&ssl=1 3x"},"classes":[]},{"id":5734,"url":"https:\/\/staging.telescoop.nl\/en\/kapteyn-b-een-planeet-uit-het-begin-van-de-tijd\/","url_meta":{"origin":14642,"position":4},"title":"Kapteyn b: A planet from the beginning of time","author":"admin","date":"28-11-2024","format":false,"excerpt":"Sommige werelden in het universum lijken rechtstreeks uit een kosmisch sprookje te komen. Kapteyn b is zo\u2019n wereld. Deze planeet, gelegen op slechts 13 lichtjaar afstand, is niet alleen fascinerend vanwege zijn nabijheid, maar vooral vanwege zijn geschiedenis. Stel je een wereld voor die bijna even oud is als het\u2026","rel":"","context":"In &quot;Astronomie 101&quot;","block_context":{"text":"Astronomie 101","link":"https:\/\/staging.telescoop.nl\/en\/astronomie-kenniscentrum\/astronomie-101\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/image-4.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/image-4.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/image-4.png?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/staging.telescoop.nl\/wp-content\/uploads\/2024\/11\/image-4.png?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":1626,"url":"https:\/\/staging.telescoop.nl\/en\/sterrenkunde-voor-kinderen\/","url_meta":{"origin":14642,"position":5},"title":"Astronomy for children","author":"admin","date":"16-09-2024","format":false,"excerpt":"Sterrenkunde kan een magische en leerzame ervaring zijn voor kinderen. Het kijken naar de sterrenhemel wekt nieuwsgierigheid en inspireert jonge geesten om na te denken over de wereld om hen heen en de eindeloze mogelijkheden van het universum. Sterrenkunde voor kinderen biedt een uitstekende manier om natuurwetenschappen te introduceren op\u2026","rel":"","context":"In &quot;Astronomie 101&quot;","block_context":{"text":"Astronomie 101","link":"https:\/\/staging.telescoop.nl\/en\/astronomie-kenniscentrum\/astronomie-101\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"_links":{"self":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/posts\/14642","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/comments?post=14642"}],"version-history":[{"count":1,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/posts\/14642\/revisions"}],"predecessor-version":[{"id":89950,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/posts\/14642\/revisions\/89950"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/media\/14643"}],"wp:attachment":[{"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/media?parent=14642"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/categories?post=14642"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/staging.telescoop.nl\/en\/wp-json\/wp\/v2\/tags?post=14642"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}