Question and Answer Session No. 1
Why do we have leap years? Does it have something to do with the day being 23 hours and 56 minutes long?
The Earth's rotation about its axis is 23 hours and 56 minutes long but the reason for a leap year has to do with the Earth's revolution about the sun. The Earth's revolution takes 365 days, 5 hours, 48 minutes and 46 seconds. That means each year we have about 6 extra hours to our year. So every four years we add an extra day to balance everything out (4 years x 6 hours = 24 hours).
Resource: timeanddate.com
How many galaxies are there?
Billions and Billions. The cool thing is that every time we build a better telescope, we find evidence of more galaxies. According to NASA, in 1999 the Hubble Space Telescope estimated that there were 125 billion galaxies in the universe. When they recently put a new camera in, HST observed 3,000 visible galaxies in only a small portion of our night sky, which was twice as much as they observed before with the old camera. Now consider that HST only collects information in the "visible" light part of the electromagnetic spectrum and the reality is that we can only detect a portion of what's out in the universe. For more about the Hubble Space Telescope, check out this web site:
http://www.stsci.edu/hst/
Most Recent Deep-Field Picture from Hubble Space Telescope
Resource: NASA - Ask an Astrophysicist
Are all planets and other things in space named after Greek and Roman G-ds?
Not anymore. There's too many objects being found in space. Newly discovered space objects get a number (the year we discovered them) and a series of letters and/or numbers.
Resource: NASA star child series - How do planets and their moons get their names?
Will the sun blow up?
Not for a very very long time (more than a billion years from now!)
Resource: NASA - Life of the Sun
What are the closest stars to us?
According to NASA, the closest solar system to us is Alpha Centari, which is about 4.2 light years away, and there are 45 stars within 17 light years from our star. Here's NASA's list of the 20 closest stars to our star and their distance in light-years. Some of these have multiple stars, but they’re considered part of the same system.
The 20 Closest Stars
Reference: Universe Today
How big is the sun compared to Earth?
1.3 million Earths could fit into the sun. Here's a link to some cool pictures:
Earth Compared to the Sun
How Big is the Sun
Scale of the Universe
How do Galaxies Form?
First you take a lot of gas, dust, and the remains of blown up stars. Let stuff that has mass start to attract other stuff that has mass, making a new bit of stuff that is more massive and attracts more mass to it. Let this continue to happen over a very long time; add pressure, heat and fusion; and eventually a very stable, rotating galaxy will be formed.
NASA | Computer Model Shows a Disk Galaxy's Life History
Where does the carbon dioxide that we are producing come from?
We get energy primarily from a 6-carbon molecule which is a carbohydrate called glucoseTo get the energy the molecules are oxidized (mixed with oxygen from the air we breathe) and a waste product is carbon dioxide which can be dissolved in the blood and exhaled through the alveoli in the lungs.
When it rains, what happens to the sun?
It's still there, you just can't see it because of the clouds.
Why do we have leap years? Does it have something to do with the day being 23 hours and 56 minutes long?
The Earth's rotation about its axis is 23 hours and 56 minutes long but the reason for a leap year has to do with the Earth's revolution about the sun. The Earth's revolution takes 365 days, 5 hours, 48 minutes and 46 seconds. That means each year we have about 6 extra hours to our year. So every four years we add an extra day to balance everything out (4 years x 6 hours = 24 hours).
Resource: timeanddate.com
How many galaxies are there?
Billions and Billions. The cool thing is that every time we build a better telescope, we find evidence of more galaxies. According to NASA, in 1999 the Hubble Space Telescope estimated that there were 125 billion galaxies in the universe. When they recently put a new camera in, HST observed 3,000 visible galaxies in only a small portion of our night sky, which was twice as much as they observed before with the old camera. Now consider that HST only collects information in the "visible" light part of the electromagnetic spectrum and the reality is that we can only detect a portion of what's out in the universe. For more about the Hubble Space Telescope, check out this web site:
http://www.stsci.edu/hst/
Most Recent Deep-Field Picture from Hubble Space Telescope
Resource: NASA - Ask an Astrophysicist
Are all planets and other things in space named after Greek and Roman G-ds?
Not anymore. There's too many objects being found in space. Newly discovered space objects get a number (the year we discovered them) and a series of letters and/or numbers.
Resource: NASA star child series - How do planets and their moons get their names?
Will the sun blow up?
Not for a very very long time (more than a billion years from now!)
Resource: NASA - Life of the Sun
What are the closest stars to us?
According to NASA, the closest solar system to us is Alpha Centari, which is about 4.2 light years away, and there are 45 stars within 17 light years from our star. Here's NASA's list of the 20 closest stars to our star and their distance in light-years. Some of these have multiple stars, but they’re considered part of the same system.
The 20 Closest Stars
- Alpha Centauri – 4.2
- Barnard’s Star – 5.9
- Wolf 359 – 7.8
- Lalande 21185 – 8.3
- Sirius – 8.6
- Luyten 726-8 – 8.7
- Ross 154 – 9.7
- Ross 248 – 10.3
- Epsilon Eridani – 10.5
- Lacaille 9352 – 10.7
- Ross 128 – 10.9
- EZ Aquarii – 11.3
- Procyon – 11.4
- 61 Cygni – 11.4
- Struve 2398 – 11.5
- Groombridge 34 – 11.6
- Epison Indi – 11.8
- Dx Carncri – 11.8
- Tau Ceti – 11.9
- GJ 106 – 11.9
Reference: Universe Today
How big is the sun compared to Earth?
1.3 million Earths could fit into the sun. Here's a link to some cool pictures:
Earth Compared to the Sun
How Big is the Sun
Scale of the Universe
How do Galaxies Form?
First you take a lot of gas, dust, and the remains of blown up stars. Let stuff that has mass start to attract other stuff that has mass, making a new bit of stuff that is more massive and attracts more mass to it. Let this continue to happen over a very long time; add pressure, heat and fusion; and eventually a very stable, rotating galaxy will be formed.
NASA | Computer Model Shows a Disk Galaxy's Life History
Where does the carbon dioxide that we are producing come from?
We get energy primarily from a 6-carbon molecule which is a carbohydrate called glucoseTo get the energy the molecules are oxidized (mixed with oxygen from the air we breathe) and a waste product is carbon dioxide which can be dissolved in the blood and exhaled through the alveoli in the lungs.
When it rains, what happens to the sun?
It's still there, you just can't see it because of the clouds.