|HubPages Device ID||This is used to identify particular browsers or devices when the access the service, and is used for security reasons.|
|Login||This is necessary to sign in to the HubPages Service.|
|HubPages Traffic Pixel||This is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.|
|Remarketing Pixels||We may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.|
|Conversion Tracking Pixels||We may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.|
Why is Pluto no longer a planet if it has moons?
Please explain what makes a planet a planet and also describe the moons of Pluto.
They broke it into two classifications. Pluto is considered a dwarf planet now. Technically we have 10 planets in our solar system (At least since last thing I read, new info might contradict me) 8 regular and 2 dwizzzzzzzarfs. =-P
According to the International Astronomical Union (IAU) a planet must satisfy three criteria:
1. It is in orbit around the Sun, as opposed to a Moon, which orbits another planet.
2. It is massive enough to achieve hydrostatic equilibrium, having formed itself into a spherical shape.
3. Has "cleared the neighborhood" of its orbit of other comparable objects, and is the gravitationally-dominant body in this neighborhood.
Pluto meets the first two criteria, but not the third. Though it is round and orbits the Sun, Pluto's orbital neighborhood, the Kuiper Belt, is littered with hundreds of other objects.
If this third criterion seems a bit arbitrary, well, it is. There was some pretty contentious debate between the pro- and anti-Pluto factions at the 2006 IAU meetings that finally set the definition of a planet. The anti-Pluto faction won the debate, and the IAU essentially wrote the definition of a planet so as to deliberately exclude Pluto. It is still controversial - after all, the Earth's neighborhood contains dozens of potentially hazardous asteroids that cross our orbital path, so we haven't quite "cleared our neighborhood" yet either.
However, it needed to be done. The definition of "planet" came from the Greek word "wanderer," referring to the way planets wandered from night to night against the background stars. This was easy to define before telescopes, but in recent years astronomers have found "wanderers" in the Kuiper Belt that are larger than Pluto and also had their own moons.
We were looking at a solar system of fifteen planets and counting - Eris, Ceres, Haumea, Makemake, Sedna, and others. Even Pluto's own "moon" Charon was also a contender for planetary status, since it doesn't really orbit Pluto. The two both pivot around a common center of gravity.
Now, we have a nice easy system - eight classical planets and five dwarves - a number certain to increase as new discoveries are made.
Planets have to have their own clear orbit around the sun, Pluto orbits with other similar objects in a region of the solar system called the Kuiper Belt. It is now classified as a dwarf planet, there are at least 3 more dwarf planets in the Kuiper Belt but probably many more.
by T156 years ago
Should Pluto be considered a planet?
by Mighty J-Kep8 years ago
Out in the belt, we find planetoids that are larger than our own Pluto.Thoughts?
by Vimesh Ummer.U5 years ago
In our solar system right now how many planets are there?
by DaniellaWood7 years ago
Is there life on other planets? What do you think?Scientific descoveries suggest that some planets are too hot or too cold for life and that others have no water and so on. But surely humans and animals canNOT be...
by Rodric Johnson6 years ago
Do you believe that there is life on other planets besides Earth and what makes you think so.There are so many schools of thought (religious and secular) about life on earth and other planets. Are we alone in the...
by sarovai6 years ago
Beyond Pluto , anything?
Copyright © 2018 HubPages Inc. and respective owners.
Other product and company names shown may be trademarks of their respective owners.
HubPages® is a registered Service Mark of HubPages, Inc.
HubPages and Hubbers (authors) may earn revenue on this page based on affiliate relationships and advertisements with partners including Amazon, Google, and others.