Answer:
Approximating the Milky Way as a disk and using the density in the solar neighborhood, there are about 100 billion stars in the Milky Way.
Explanation:
Since we are making an order of magnitude estimate, we will make a series of simplifying assumptions to get an answer that is roughly right.
Let's model the Milky Way galaxy as a disk.
The volume of a disk is:
V
=
π
⋅
r
2
⋅
h
Plugging in our numbers (and assuming that
π
≈
3
)
V
=
π
⋅
(
10
21
m
)
2
⋅
(
10
19
m
)
V
=
3
×
10
61
m
3
Is the approximate volume of the Milky Way.
Now, all we need to do is find how many stars per cubic meter (
ρ
) are in the Milky Way and we can find the total number of stars.
Let's look at the neighborhood around the Sun. We know that in a sphere with a radius of
4
×
10
16
m there is exactly one star (the Sun), after that you hit other stars. We can use that to estimate a rough density for the Milky Way.
ρ
=
n
V
Using the volume of a sphere
V
=
4
3
π
r
3
ρ
=
1
4
3
π
(
4
×
10
16
m
)
3
ρ
=
1
256
10
−
48
stars /
m
3
Going back to the density equation:
ρ
=
n
V
n
=
ρ
V
Plugging in the density of the solar neighborhood and the volume of the Milky Way:
n
=
(
1
256
10
−
48
m
−
3
)
⋅
(
3
×
10
61
m
3
)
n
=
3
256
10
13
n
=
1
×
10
11
stars (or 100 billion stars)
Is this reasonable? Other estimates say that there are are 100-400 billion stars in the Milky Way. This is exactly what we found.
1). Sequence from the Sun:
Inner planets:
Mercury
Venus
Earth
Mars
Outer planets:
Jupiter
Saturn
Uranus
Neptune
2). The farther a planet is from the sun, the longer it takes
to orbit the sun. Mercury ... 88 days. Earth ... 365 days.
Jupiter ... 12 years. Neptune ... 165 years.
3). Mercury & Venus ... no moons
Earth - 1
Mars - 2
Jupiter - more than 65
4). Mercury ... cratered, no atmosphere
Venus ... cratered, thick cloudy atmosphere
Mars ... dry, cratered, slight atmosphere, like 1% or Earth's
Jupiter, Saturn, Uranus, Neptune
We can't see any surface. If any of them even
HAS a surface, it's thousands of miles under a
thick atmosphere of methane gas.
5). Missing from the list
6). Here's a list from the biggest planet to the smallest one.
The numbers in parentheses are the radius of the planet --
half of the diameter:
Jupiter (69,911 km / 43,441 miles) – 1,120% the size of Earth
Saturn (58,232 km / 36,184 miles) – 945% the size of Earth
Uranus (25,362 km / 15,759 miles) – 400% the size of Earth
Neptune (24,622 km / 15,299 miles) – 388% the size of Earth
Earth (6,371 km / 3,959 miles)
Venus (6,052 km / 3,761 miles) – 95% the size of Earth
Mars (3,390 km / 2,460 miles) – 53% the size of Earth
Mercury (2,440 km / 1,516 miles) – 38% the size of Earth
7). At least seven of the planets rotate in the same direction.
There's something different about one of them ... it may be Uranus
but I'm not sure. You'll have to look this up.
8). Saturn has the famous rings, that you can almost see
with only binoculars.
Spacecraft sent to observe the outer planets have detected
very thin rings around Uranus and Neptune.
9). Included in #6.
10). I don't have complete info. Generally, the closer the planet
is to the sun, the hotter it is. But there are a few exceptions.
I think Venus ... the second one from the sun, is actually hotter
than Mercury.
11). Just about every language has its own name for each planet.
12). "Terrestrial" means "like Earth" ("Terra").
The terrestrial planets are the ones that have solid surfaces
and are made of rock.
Mercury, Venus, Earth, and Mars.
13). "Jovian" means "like Jupiter".
Either no solid surface, or very small, inside a big deep gas ball.
Jupiter, Saturn, Uranus, Neptune.
Answer:
The answer is conductor
Explanation:
HOPE THIS ANSWER HELP YOU
Answer:
334.314 (kJ)
Explanation:
1) the formula for the required energy is: Q=c*m(Bp-t), where c - 4100 J/kg*C; m - 0.9 kg; Bp - 100.6 C; t - 10 C.
2) according to the formula above:
Q=4100*0.9*(100.6-10)=41*9*906=334314 (J).
