Dear Mark, I've heard that the centre of the Milky
Way has a black hole. If this is true, wouldn't we have been sucked up
already or something?
SHANE, AGE 13, SPOKANE, WASHINGTON, US
Answer: It is true that
we think there might be a black hole at the centre of the Milky Way but
we are about 247 million billion km away from it. The pull from the black
hole is not strong enough to affect us too much at that distance.
A sun spot |
Does is take 365 days for the earth to orbit the sun
or 364 1/4?
GLYN, AGE 10, FELIXSTOWE
Answer: It takes the Earth
365 1/4 days to go around the Sun once.
What does a comet orbit?
JACKIE, AGE 11, IN BALTIMORE, USA
Answer: All comets in our
Solar System orbit around the Sun.
What do you call the outer atmosphere of the Sun?
BROOKIE, AGE 11, OSHAWA
Answer: The outer atmosphere
of the Sun is called the Corona. We can only see it clearly during a solar
eclipse when the Moon blocks the rest of the light from the Sun.
Who was the first person to discover that planet Earth
is round?
JOEL, KUMASI
Answer: The first people
to discover the Earth was round were the Greeks in 500BC. They often would
watch lunar eclipses where the Earth blocks sunlight from reaching the
Moon.
This meant the Moon passed through the Earth's shadow.
The Greek astronomers noticed the shadow had a round edge. This was all
confirmed by Christopher Columbus in 1492.
Do any of the planets grow or get bigger?
KAYLA, AGE 13, MT MESA
Answer: It is not thought
that any of the planets grow or get bigger. They do change shape very
slightly due to the effects of tides but they do not gain much weight.
How does the earth move in a year and why do we get
day and night?
JACK, AGE 10, SHREWSBURY
Answer: The Earth moves
around the Sun in a path we call its orbit. It takes the Earth one year
to go around the Sun once. Whilst it is doing that, it is also spinning
around like a spinning top.
It takes about 24 hours for the Earth to spin once and,
when the Sun is in the sky we have daytime, but when the sky is no longer
in the sky we have night time.
Astronaut |
How far away is the planet Earth away from the Sun?
AMANDEEP, AGE 10, WELLESBOURNE
Answer: The Earth is about
150 million km from the Sun, although sometimes it is closer and sometimes
a little further away.
Are Sedna and Quauoar part of our solar system?
ANON, AGE 10
Answer: Yes, Sedna and
Quaoar are thought to be part of our Solar System. They are generally
thought too small to be called planets so we think of them more as asteroids
or minor planets.
How do astronauts breathe in rockets without wearing
spacesuits?
HABEN, AGE 12
Answer: Astronauts can
breathe in rockets without spacesuits because air (oxygen) is pumped into
the rocket.
The supply is limited so they have to make sure there
are no delays in the flight.
If you were travelling at the speed of light in the
dark and you put your headlights on, would you see anything?
GRAHAM ALLINSON, AGE 46
Answer: If you were travelling
at the speed of light, then the first thing you will notice is flashing
blue lights in your rear view mirror!
Ok, the first thing to note is that you wouldn鈥檛 see
any particularly unusual affects inside the car as everything would be
travelling at the same speed.
The light coming out of the car headlights would still
be travelling at the speed of light relative to your car so again, you
wouldn鈥檛 notice anything different.
You would notice something strange if you looked outside
the car. The light coming out of the headlights would illuminate items
ahead and the light would get reflected back as usual.
Those objects will be travelling toward you at the speed
of light so the reflected light will be significantly blue shifted toward
the ultraviolet and further.
If you were to try and photograph things outside your
car with a very fast camera, you would see that objects were contracted
in length due to the different times for the passage of light.
All in all, it would be a pretty wacky experience.
How far apart are the Earth
and the Sun?
BETHANY, AGE 11
Answer: The Earth and Sun
are about 150 million km apart. This does change though because the path
the Earth follows around the Sun is quite like a squashed circle.
We call this shape, an ellipse. This distance is also
called an astronomical unit and is a measurement we use in the Solar System.
The Earth-Sun distance is 1 astronomical unit.
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