PV Gap

Jean Said:

Astronomy. How many planets are in our solar system?

We Answered:

8 and pluto or 9 if you include pluto. Pluto isnt technically a planet. And there are thousands of other solar systems but the are all lightyears away.

Suzanne Said:

How many planets are known to be in our solar system?

We Answered:

There are 9 planets that are proven. Xena is not substantiated as a planet, but it is hypothesized. Some people are still uncertain whether it's a star or planet.

Linda Said:

How many planets in our solar system rotate on their axis as they orbit the sun?

We Answered:

First part of your question-----all of them. All planets rotate on their axes.

Second part-----The axial tilts vary from 3 degrees (Jupiter), through Earth(23 1/2 degrees.)All are fairly close to Earth's except Uranus, which "lies on its side" so to speak, and rotates "up and down" instead of East and West.

Ruth Said:

How many days would it take an average space craft to get to ' planets in our solar system'?

We Answered:

Voyager 2 Spacecraft times that visited ever single planet outside the Asteroid Belt.....

Voyager 2 was launched on August 20, 1977
The closest approach to Jupiter occurred on July 9, 1979
The closest approach to Saturn occurred on August 26, 1981
The closest approach to Uranus occurred on January 24, 1986
The closest approach to Neptune occurred on August 25, 1989

Mariner 10 visited Venus and Mars...
launched on November 3, 1973
The spacecraft passed Venus on February 5, 1974
The first Mercury encounter took place at 20:47 UT on March 29, 1974

Mars Reconaissance Orbiter visited Mars...
On August 12, 2005, MRO was launched aboard an Atlas V-401 rocket
MRO began orbital insertion by approaching Mars on March 10, 2006

I think that might help you. Just calculate the time between each for what a spaceship has done.

Gregory Said:

How many planets of our solar system would this star engulf?

We Answered:

use the radiation flux equation it shows for a given temperature how much flux of energy(energy per unit of surface area) is emitted by a gas. Then from that equation find a sphere that has a surface area that in total has 20 000 solar luminosity. From the surface area given it is easy to find the radius by simple spherical geometry.
You basically just have to find that equation which should be in any elementary textbook or find it online and plug in your numbers.