- A.) Planet:
Body in space which orbits a star (eg the Sun).
Traditionally, nine planets orbiting the Sun
have been recognized.
definition of planet was changed recently so that the planet Pluto,
and other similar bodies are now called "dwarf planets". Planets
orbiting other stars are called "extrasolar planets"
- B.) Star:
A large gaseous sphere which produces energy and light
by nuclear fusion.
The all the planets collectively, including the Sun, Moon,
asteroids and comets. Ie, the Sun and all that orbits it.
An assemblage of millions to billions of stars together with
gas and dust. The Sun, and our solar system reside a galaxy called
the Milky Way.
Everything; All which is, including all galaxies, and all
space between them.
The Speed of the Earth 30,000 km/s. Express
this number in km/s and miles per second.
Unit Conversions: We can always convert from one set of
units (eg, km) to another (m) by multiplying by a fraction
equal to 1. Since 1000m = 1 km, the fraction:
(1km /1000 m) = 1
Hence, 30,000 m/s *( 1km/1000 m) = 30 km/s
Similarly, since 1km = 0.6 miles
30 km/s * (0.6 miles / km ) = 18.6 miles per second
There aren't any months in 3 light years,
because a light year is a measure of distance,
while a month is a measure of time. The question makes
no sense, like saying, "How many inches until Friday?"
- What is the ecliptic, and why is it tilted
with respect to the equator"
The ecliptic is the plane in which the Earth orbits the Sun. Or, as
seen from the Earth, the Ecliptic is a line in the sky in which the
Sun always appears.
The Celestial Equator is a line in the sky above the Earth's equator.
It is perpendicular to the axis of the Earth. But Earth's axis is not
perpendicular to the Ecliptic Plane. The Ecliptic and Equator
are by tilted about 23.5 degrees with respect to each other.
For a solar eclipse to occur, the Moon's shadow must be cast on the Sun.
This can only happen at New Moon phase. Those directly in the shadow,
on the "Path of totality" see the Sun disappear.
The August 21 2017 eclipse was total for those along the path of totality,
but parital in San Francisco. It was also very cloudy in SF that day, so
most people missed it!
Seasons are caused by the tilt of Earth's orbit with respect to the
ecliptic plane. As Earth orbits the Sun this tilt causes the
Sun to shine more directly on some parts of Earth than others.
These parts of the world see the Sun in the sky for more
hours of the day, and thus experience hotter temperatures
A.) The Earth Orbits the Sun once each year.
B.)The number of seconds in a year is:
365 days/year x 24 hours/day x 60 minutes/hour x 60 seconds/minute
= 3.15 x 10 7 (31 million) seconds in a year.
If you are 20 years old then you are 620 million seconds old.
The "National Debt" is the total amount of money which the United
States has borrowed, and not yet payed back. This money must be payed
back, eventually, by US taxpayers. Look up the current national debt,
in dollars, and write this number in both scientific notation
and in long form (feel free to round the number off).
20 trillion dollars = $20,000,000,000,000 = $20.0 x 1012.
(Around Twenty Trillion dollars..and it is growing
by about $2 billion per day).
- If you won the lottery
1000 times would you have enough money to pay off the national debt?
(Note that 1 Trillion = 1,000 Billion, and 1 Billion = 1,000 Million.)
One thousand lottery wins of would produce:
1000 x $1.5 billion = $1.5 trillion which is not even 1 tenth
of the national debt.
A lottery win is a large amount of money.
But the national debt is a HUGE amount of money.
In 2000, the debt was $6 trillion and shrinking; in the last 15 years
it more than tripled! We are now paying over $400 Billion
a year in INTEREST on the debt (and only $15 billion for NASA, $65
billion for Education, etc. see www.federalbudget.com )
In fact if you won the lottery every day and used all
the money to pay down the debt, you still couldn't pay it
off because it increases each day by more than
you are winning!
$250 billion/$7.5 billion = 250/7.5 = 33.3.
The U.S. spends about 33 times more on interest paying
off the national debt than on the NSF.