Topic: Mathematician needed!!

[Brutus]

i know this is along shot but i dunno what else to do.

i am in an argument with a young earth creationist who i am absoloutly determined to prove wrong and i need to work out how many tonnes of mass would be needed to be added to to the sun to increase its diameter by 93 million miles. now while i have all the data i never seem to comeout with the correct answer or i just get lost in the sums and have to start again.

then i remembered that this forum has some people on who are very good at maths so i just want to ask for a few minutes of their time.

i am not completely sure of what information is needed to calculate this but i do have this

the suns diameter is 870000 miles
its circumference is 2717000 miles
its mass is 2.191874×10 to power of 27 tonnes

if you need any more info i will get it for you and save you having to look for it.

[Oviraptor]

Technically, the sun doesn't have to gain any mass. It's density could just go down.

[Brutus]

his argument is based around the mass of the sun.

[SmileyMan]

Bah. Creationists..

[Brutus]

would it be correct if i worked out how much (proportionatly) 870000 would have to increase by to get to 93870000 and then increase the current mass of the sun by that amount? or does mass increase exponetially when compaired with circumference, damn i think it does.

[Neoadept]

Your arguing about how much more mass the sun would need to expand to engulf the earth without changing density, right?  In that case you want radius, not diameter.  The only known star of comparable size is the Pistol Star, with a rough radius of 100 million miles.  It has about one hundred times the mass of the sun, but a much lower density.  If anything got to that size without a change in density it wouldn't be around for too long before collapsing into a neutron star or black hole.

[Daxx]

The mass won't go up or down when the Sun starts to expand. The density will change.

EDIT: Think about it. Where would all this mass come from? The reasons stars expand is not because they become more massive, but because the strength of the nuclear forces within them change.

[Oviraptor]

4/3 * pi * (r)³

That's how you find volume.

mass / volume = density

So:

    2.191874×10²⁷      = Density of Sun
4/3 * pi * (435000)³

density * volume = mass

So:

Density of sun * [4/3 * pi * (93000000)³] = mass of the Sun with a radius of 93 million miles.

Enjoy.

[Brutus]

he says that since the sun loses 5 million tonnes of mass a second through nuclear fission (yes, i know its actually 4) then that means if you go backwards through time the sun would gain 5 miillion tonnes of mass a second and be  nig enough to engulf the earht within a few million years meaning the sun cannot be millions of years old and this supports the young earth claim.

now i know that their are various iother flaws in his claim but i want to prove him wrong using maths and so my argument is airtight.

THANK YOU OVI!!

[Krakow Sam]

Ummm. Maybe it would be easier to correct him by point out that the sun is a fusion reaction, not fission.

[Brutus]

eeerm thats my typo. i now feel stupid

[Daxx]

he says that since the sun loses 5 million tonnes of mass a second through nuclear fission (yes, i know its actually 4) then that means if you go backwards through time the sun would gain 5 miillion tonnes of mass a second and be  nig enough to engulf the earht within a few million years meaning the sun cannot be millions of years old and this supports the young earth claim.

now i know that their are various iother flaws in his claim but i want to prove him wrong using maths and so my argument is airtight.

THANK YOU OVI!!

Without actually calculating it, I know that 5 million tonnes is not very much compared to the actual mass of the sun which runs to 1.98892 × 10³⁰ kilograms. That's 1.98892 × 10²⁷ tonnes.

So, the Sun would have 3.97784 × 10²⁰ seconds left in its lifetime. That's 1.26136479 × 10¹³ years left.

Now consider that that's well over the current age of the Universe, and that's for a Sun with a radius of only 695 500 km.

I'll work out exactly how large the sun would have been 14 billion years ago even if this ridiculous concept had no other flaws in it in a second.


Let's work with 14 billion years as the age of the Universe. That's 4.41796964 × 10¹⁷ seconds.

4.41796964 × 10¹⁷ seconds x 5,000,000 tonnes per second = 2.20898482 × 10²⁴ tonnes = 2.20898482 × 10²⁷ kilograms

Density of the Sun = 1,409 kg/m³

This means the Sun would have had (at the beginning of the Universe) a volume of 1.56776779 × 10²⁴ m³ more.

That's approximately 27733540 metres extra in radius. That's a grand total of 17233 miles.

We are about ninety three million miles away from the sun.

Can someone double check this for me?

[Brutus]

what i need to know is how many years it would take (if the sun was always at its current denisty) for the sun to become big enough to engulf the earth if it gained 5 million tonnes of mass every second.

[Daxx]

Far longer than the age of the universe, by my calculations.

[Brutus]

ah, but could you give me a number rounded to the nearest million years? or so.

he could just lie his way round it if i don't give a number

i am so thankful for all your help.