The Scale of the Solar System

The solar system is almost entirely empty space. Distances between planets are so enormous that even our fastest spacecraft take years to reach them. Explore just how vast our cosmic neighbourhood really is.

40 XP

Reward

10

Questions

5–10 min

Time

Q1 Question 1 of 10

In a scale model where the Sun is the size of a basketball (about 24 cm across), how far away would Earth be?

About 1 metre away About 26 metres away — roughly the length of a classroom building About 1 km away About 800 metres away

Q2 Question 2 of 10

Using the basketball-Sun scale model, approximately how far away would the nearest star (Proxima Centauri) be?

About 1 km away — just a short walk About 7,000 km away — roughly the distance from Australia to London About 100 km away — on the other side of the city About 1 million km away — past the Moon

Q3 Question 3 of 10

How long does it take light to travel from Earth to Mars at the closest approach between the two planets?

About 8 seconds About 3 minutes About 8 minutes About 4 hours

Q4 Question 4 of 10

Voyager 1 was launched in 1977 and is now over 23 billion km from Earth. About how long does a radio signal take to travel from Voyager 1 to Earth?

About 8 minutes About 1 hour Over 21 hours About 4 days

Q5 Question 5 of 10

What is the Oort Cloud, and approximately how far does it extend from the Sun?

A ring of asteroids between Mars and Jupiter extending up to 5 AU A distant spherical reservoir of comets thought to extend up to 100,000 AU from the Sun A cloud of gas and dust 10 light-years from the Sun Neptune's outermost moon, orbiting at 500 AU

Q6 Question 6 of 10

What fraction of the solar system (by volume) is actually filled with planets, moons, and other solid objects?

About half — the solar system is fairly densely packed About 10% — it is mostly empty but not completely About 1% — there are many small objects filling the gaps An extremely tiny fraction — the solar system is almost entirely empty space

Q7 Question 7 of 10

The New Horizons spacecraft flew past Pluto in 2015 after a journey of about 9 years. Pluto was about 32 AU from Earth at that time. How fast was New Horizons traveling?

About 14 km/s — fast enough to cross the USA in about 6 minutes About 300,000 km/s — the speed of light About 0.1 km/s — about as fast as a commercial jet About 1,000 km/s — 1,000 times faster than a jet plane

Q8 Question 8 of 10

Light from the Sun takes about 8 minutes to reach Earth. Approximately how long does it take to reach Neptune?

About 8 minutes — the same as Earth About 30 minutes About 4 hours About 1 day

Q9 Question 9 of 10

When the Voyager probes were launched in 1977, they used a rare alignment of the outer planets to complete a grand tour. What technique let them speed up as they passed each planet?

Ion drives — electrically charged gas expelled for extra thrust Solar sails — large reflective panels pushed by sunlight Nuclear rockets — more powerful than chemical rockets Gravity assist (gravitational slingshot) — flying close to a planet steals a tiny amount of the planet's orbital momentum

Q10 Question 10 of 10

Which of the following best explains why we have not yet sent astronauts beyond the Moon, even though we have robotic probes visiting all the outer planets?

Astronauts are too heavy for rockets to carry to other planets There is no oxygen between the planets so astronauts cannot breathe in space It is against international law to send humans beyond the Moon The distances and travel times to other planets are enormous — reaching Mars takes 6-9 months even with current technology, requiring life support for a multi-year mission

Report a Problem