Astronomy questions from kids, Part 4

My friend Tina is a teacher in Austin. She asked her sixth grade students to send me questions they had about astronomy, and I answer them on camera. There were so many I had to split this into *5* parts!

This is Part 4, and these are the questions they asked me:

1) Is there another planet past Pluto or inside Mercury's orbit?

2) Why can't we live without the Sun?

3) How do stars form?

4) Have the constellations changed?

5) Why is space black? Why doesn't the Sun light it up?

6) Do galaxies move around in space and do they collide?

7) What is the biggest galaxy?

Category:

Education

Tags:

• phil plait
• bad astronomy
• astronomy
• science
• students
• Pluto
• aliens
• planets
• Moon
• Mars
• space

[Atheistprimate]

Thank you for your videos, you make astronomy fun to think about by how you describe things.

[bobnfreely]

I love these videos, but I'm not crazy about your answer to the question about why the sun doesn't light up space. A better answer would discuss how we can only see light when it is shining (stars) or reflected (planets) into our eyes, and how the intensity of light diminishes with distance.

[TheCrimsonIdol987]

@Biarry: MUCH MUCH MUCH shorter than that. Earth is about 150 million kilometers from the sun (or 1 AU), light travels at 299,793 kilometers per second. When you calculate the math, it's more like 8 minutes plus or minus 30 seconds.

[jqs1943]

Albert Einstein redifined gravity. I've RE-redifined it as having a secondary field component which i've named the X-gravity field factor. Both gravity and X-gravity have a cumulative force that oppoerate in opposite directions starting at the plane of the exosphere of .0735 lbs. per sq.in. per linear mile of expansion. (Do the math all pertinent info is obvious) The gravitational force fields of each planet differentiate from others as a consequence of the heat intensity of the planet's core.

[MyMainMan09]

I havnt watched this video yet, but saw "Why cant we live without the sun", thats because its warmth gives us the living temperature

[CapPicard]

LOL at the one called Vulcan. I didn't know that honestly. But I do remember someone saying that Vulcan was rumored to be an exoplanet orbiting the red dwarf 40 Eridani-A.. Nothing found around that star yet.

I read that a trinary star system actually was found to have a planet orbiting the primary with the secondary stars orbiting the first star. It would be awesome to see the sky of said planet (three suns as opposed to our one).

[shitsons]

lol i was just guna write that, nice comment

[UneX100]

Better explanation in the question why space is black , because space is empty and light is invisible , and we can see planets because they reflect light of the sun

[didjabringadidjalong]

no prob.

you can track and follow all kinds of instruments at nasa's website, check it out

[candlehawk]

Thanks!

[didjabringadidjalong]

13.23 AU from earth

almost halfway