Kids in Land of the Rising Sun in the dark over astronomy

[puargs]

Story:

TOKYO (AFP) - They may come from the Land of the Rising Sun, but many Japanese children do not know the solar body sets in the west and also think it circles the Earth, a researcher at the National Astronomical Observatory of Japan said.
...
In one survey of 720 pupils, 27 percent did not know that the Sun sets in the west, while two percent explained the Moon's waxing and waning by choosing the explanation "the Moon has many shapes".

In another sample, out of 348 students asked to circle the correct statement to describe the Earth's orbital relationship to the Sun, 42 percent circled "the Sun goes around the Earth", while 56 percent picked the correct answer.

Only 39 percent correctly answered that the Moon orbits the Earth in the same way as man-made satellites.

Anyone else find this a little weird? Didn't I know this in America before I even started school?

[kurohinge1]

Almost as bad as banning the teaching of evolution

... Agata said that under the Japanese elementary school curriculum introduced in 2002, teachers only explain the movement of the Sun, the Moon and the stars as viewed from the perspective of the ground.

"This is a case of students answering as they are taught rather than them just making a mistake," he said.

Agata also noted students in rural areas with more experience of outdoors more often answered correctly than children from Japan's brightly-lit cities where the night sky is only dimly visible.

Maybe the sun really does revolve around the Earth - I mean, has anyone been up there to check?

But I do have a question for any budding astronomers:

We were taught in school that the sun, in its dying stages, will expand to become a red giant before shrinking to a white dwarf. However, if the sun converts mass to energy, isn't it losing mass? And if the incredible mass of the sun balanced by the speed of Earth's orbit is what keeps us in orbit, won't a reduction in that mass result in the Earth flying off into space, footloose and fancy free?

Or are the relative margins so wide that it won't make a difference?

Or should I stop taking the green pills with the red ones?

BTW I can tell you how to find South using your watch and the sun, if you're interested.

[puargs]

My understanding is this: Stars do not lose mass when they change forms. It will start expanding, but maintain the same mass. The only difference is the way the fusion is occurring in the core, first it burns hydrogen, then helium, and so on. Stars have 4 ways to go: Brown Dwarf, White Dwarf, Supernova, or Black Hole. Stars less than .6 solar masses don't have enough mass to ignite nuclear fusion, and as such undergo a contraction-heating (I've forgotten the name.. Helmholtz something) that burns dull (at least in comparison to regular stars anyway-no real fusion). Stars between .6 solar masses and 1.4 solar masses are like our own- they evolve from regular star to big, fat, and red, to white dwarf. The mass stays the same during the red dwarf transition phase- it's just, it burns a LOT faster, a LOT hotter, and a LOT brighter. After this phase, it sheds a "shell" of debris (that's the only mass loss) and semi-collapses to a white dwarf.

Solar masses over 1.4 but less than 4.2 go nova or supernova and blow the hell up. This is because the fusion reaction can be sustained because of the higher mass, and it continually burns higher and higher elements, creating at least trace amounts of every element on the periodic table (this is how elements were originally formed, from supernovae). This process moves faster and faster, and after Iron starts to burn, watch out- it's gonna blow. After that point is "heavy" element fusion.. just gets hotter and hotter. Boom.

Solar masses over 4.2 are so massive they collapse into a black hole before being able to go supernova. Suckas!

As for the Earth.. when our sun dies out, the Earth will remain in orbit, it'll just be burned to all hell by the red giant. After the sun collapses to shed its shell, the shell will become a planetary nebula. Perhaps earth will have a bunch of new neighbor planets.

[dingosatemybaby]

My understanding is this: Stars do not lose mass when they change forms. It will start expanding, but maintain the same mass. The only difference is the way the fusion is occurring in the core, first it burns hydrogen, then helium, and so on. Stars have 4 ways to go: Brown Dwarf, White Dwarf, Supernova, or Black Hole. Stars less than .6 solar masses don't have enough mass to ignite nuclear fusion, and as such undergo a contraction-heating (I've forgotten the name.. Helmholtz something) that burns dull (at least in comparison to regular stars anyway-no real fusion). Stars between .6 solar masses and 1.4 solar masses are like our own- they evolve from regular star to big, fat, and red, to white dwarf. The mass stays the same during the red dwarf transition phase- it's just, it burns a LOT faster, a LOT hotter, and a LOT brighter. After this phase, it sheds a "shell" of debris (that's the only mass loss) and semi-collapses to a white dwarf.

Solar masses over 1.4 but less than 4.2 go nova or supernova and blow the hell up. This is because the fusion reaction can be sustained because of the higher mass, and it continually burns higher and higher elements, creating at least trace amounts of every element on the periodic table (this is how elements were originally formed, from supernovae). This process moves faster and faster, and after Iron starts to burn, watch out- it's gonna blow. After that point is "heavy" element fusion.. just gets hotter and hotter. Boom.

Solar masses over 4.2 are so massive they collapse into a black hole before being able to go supernova. Suckas!

As for the Earth.. when our sun dies out, the Earth will remain in orbit, it'll just be burned to all hell by the red giant. After the sun collapses to shed its shell, the shell will become a planetary nebula. Perhaps earth will have a bunch of new neighbor planets.

Yes, but will smellevision have replaced television by then?

[kurohinge1]

Impressive answer puargs-san.

I nominate you to fix the Japanese curriculum.

However my question about mass loss was conerning the life of the star before the red giant stage. Do they lose mass normally - from giving off radiation / fusion?
Isn't it the loss of mass that results in them expanding to become red giants?
If so, my query about how fixed our orbit is still remains. Or is it simply the fact that any mass converted to energy is not sufficient to alter things?

Where are those pills ...

[cstaylor]

Impressive answer puargs-san.

I nominate you to fix the Japanese curriculum.

However my question about mass loss was conerning the life of the star before the red giant stage. Do they lose mass normally - from giving off radiation / fusion?
Isn't it the loss of mass that results in them expanding to become red giants?
If so, my query about how fixed our orbit is still remains. Or is it simply the fact that any mass converted to energy is not sufficient to alter things?

Where are those pills ...

The amount of mass converted to energy in fusion is pretty small IIRC.

[puargs]

Ah. Good question, no- it's the conversion of hydrogen to other materials that changes the phase of the star. A lot of it actually undergoes another reaction to turn it back into hydrogen again, and is re-fused. But eventually this fuel runs out, it turns into other normally non-fusable materials (This includes the heavy elements that are fused later, after the phase change).

At least, that's what I think. I could be wrong!

[puargs]

Erm. I realized that didn't answer anything. The above post means in short that no appreciable mass is lost, no. At least, not enough to throw objects completely out of orbit.

For supernovae, something cooler happens. Basically everything is destroyed in the star system, and everything within a few light years (!) is inundated with radiation (for example, if Proxima Centauri were to go supernova [4.2 light years away], probably everything on Earth would die).

[scorpinitorex]

This doesn't have to do with your discussion, buuuut. . .Here at UHM I study a bit of astronomy ahahahah. Funny thing is many students who speak up in class here know just about as much as these Japanese students!

[Caustic Saint]

BTW I can tell you how to find South using your watch and the sun, if you're interested.

I bet you can't.

[cliffy]

BTW I can tell you how to find South using your watch and the sun, if you're interested.

I bet you can't.

Old scouting joke: Throw the digital watch over left shoulder, it has now "Gone west", using your knowlege of the compass points you can now buggger off and stop annoying me in any direction you choose.


I got this from an old Queens scout, so don't blame me......much

[maraboutslim]

BTW I can tell you how to find South using your watch and the sun, if you're interested.

I bet you can't.

Cute. But it's still easy. As long as you know what time it is, to the nearest hour, from your digital watch, from asking a person passing by, whatever, you can find south.

Just picture a circle in your head or draw one on the ground or whatever and picture or draw a line corresponding to where the hour hand would be if it was an analog clock and south is between that and where 12 would be.

"the....sun is a mass of incadescent gas, a gigantic nuclear furnace..."

[GridReaper]

BTW I can tell you how to find South using your watch and the sun, if you're interested.

My Suunto watch does that nicely already.

[

[Caustic Saint]

BTW I can tell you how to find South using your watch and the sun, if you're interested.

I bet you can't.

Cute. But it's still easy. As long as you know what time it is, to the nearest hour, from your digital watch, from asking a person passing by, whatever, you can find south.

Yeah, I learned how to do that in the army. I was just being cheeky is all.

[kurohinge1]

Caustic Saint, your current avatar is freaking me out. Very nice, though.
Your point about the digital watch is sadly true as I've watched kids
who've only ever owned digital watches struggle to understand this trick.

As you guys know, south is halfway between the 12
& the hour hand, when you point the hour hand at the sun.
However, this is only for the northern hemisphere.

In the southern hemisphere, north is halfway between the 12
& the hour hand but only when you point the 12 at the sun.

Of course, it it's cloudy, you're stuffed.

[Caustic Saint]

Caustic Saint, your current avatar is freaking me out. Very nice, though.

If you think that one's freaky, check this one out:



It's not animated!

I have a bigger version I've tried using as a desktop before, but it's way too distracting.

[dimwit]

Almost as bad as banning the teaching of evolution

... Agata said that under the Japanese elementary school curriculum introduced in 2002, teachers only explain the movement of the Sun, the Moon and the stars as viewed from the perspective of the ground.

"This is a case of students answering as they are taught rather than them just making a mistake," he said.

Of course, ALL Japanese know that the world revolves around Tokyo.