1. How many planets are in our solar system?
8
Eight planets orbit the Sun; Pluto was reclassified as a dwarf planet in 2006.
2. Which planet is closest to the Sun?
Mercury
Mercury is the innermost planet, whipping around the Sun in just 88 days.
3. Which planet is the hottest in the solar system?
Venus
Venus beats Mercury because its thick carbon dioxide atmosphere traps heat like a runaway greenhouse.
4. Why does Mars look red?
Its surface is covered in rusty iron oxide dust
Iron minerals in the Martian dust have rusted, giving the whole planet its red colour.
5. Which is the largest planet in our solar system?
Jupiter
Jupiter is so big that more than 1,300 Earths could fit inside it.
6. Which planet is famous for its bright, easily seen rings?
Saturn
Saturn's rings are made of countless chunks of ice and rock.
7. What happened to Pluto in 2006?
It was reclassified as a dwarf planet
Astronomers agreed on a new definition of planet, and Pluto became the most famous dwarf planet.
8. What is the Sun?
A star
The Sun is an ordinary star that just happens to be very close to us.
9. How does the Sun make its energy?
By nuclear fusion, squeezing hydrogen into helium
Deep in its core the Sun fuses hydrogen into helium, releasing enormous energy.
10. About how long does sunlight take to reach Earth?
8 minutes
Light crosses the 150 million km from the Sun to Earth in about 8 minutes.
11. What is a light year?
The distance light travels in one year
A light year measures distance, about 9.5 trillion kilometres.
12. What is the nearest star to the Sun?
Proxima Centauri
Proxima Centauri is about 4.2 light years away, part of the Alpha Centauri system we can see from NZ.
13. Roughly how old is the Sun?
4.6 billion years
The Sun and the whole solar system formed about 4.6 billion years ago.
14. What will the Sun eventually become when it runs low on hydrogen fuel?
A red giant
In about 5 billion years the Sun will swell into a red giant, then fade to a white dwarf.
15. Why do stars appear to twinkle?
Earth's moving atmosphere bends their light
Wobbling air in our atmosphere bends starlight around, which we see as twinkling.
16. What is a black hole?
An object with gravity so strong that not even light can escape
A black hole packs so much mass into so little space that light itself cannot escape its gravity.
17. What causes Earth's seasons?
The tilt of Earth's axis as it orbits the Sun
Earth is tilted about 23.5 degrees, so each hemisphere leans towards the Sun for part of the year.
18. Why is it summer in New Zealand in December?
The southern hemisphere is tilted towards the Sun then
In December the southern half of Earth leans sunward, so we get long hot days while the north shivers.
19. How long does Earth take to spin once on its axis?
About 24 hours
One full spin takes about 24 hours, which is why we have day and night.
20. How long does Earth take to orbit the Sun once?
365.25 days
One orbit takes 365 and a quarter days, and the quarter days add up to a leap day every four years.
21. About how long is a full cycle of Moon phases, from full moon to full moon?
About 29.5 days
The Moon runs through all its phases in about 29 and a half days.
22. What mainly causes the ocean tides?
The Moon's gravity pulling on Earth's oceans
The Moon's gravity (helped by the Sun's) drags the oceans into bulges that we experience as tides.
23. What is a solar eclipse?
The Moon passing between the Sun and Earth
In a solar eclipse the Moon blocks our view of the Sun and casts its shadow on Earth.
24. What is a lunar eclipse?
Earth's shadow falling on the Moon
In a lunar eclipse Earth sits between the Sun and Moon, and our shadow turns the Moon a coppery red.
25. Where is the asteroid belt?
Between Mars and Jupiter
Most asteroids orbit in a belt between Mars and Jupiter.
26. Which way does a comet's tail point?
Always away from the Sun
Sunlight and the solar wind blow the tail away from the Sun, whichever way the comet is moving.
27. What is a shooting star really?
A meteor, a bit of space rock burning up in our atmosphere
Shooting stars are meteors, tiny bits of rock or dust blazing as they hit our atmosphere.
28. What do we call a space rock that survives its fall and lands on the ground?
A meteorite
Once it reaches the ground it is a meteorite; while it burns in the sky it is a meteor.
29. What is the name of our galaxy?
The Milky Way
We live in the Milky Way, a spiral galaxy of billions of stars.
30. One te reo Māori name for the Milky Way, pictured as a great fish of the sky, is:
Te Ikaroa
Te Ikaroa, the long fish, stretches across the summer sky (Mangōroa, the long shark, is another name).
31. What is the nearest large galaxy to the Milky Way?
Andromeda
Andromeda is about 2.5 million light years away and is slowly heading our way.
32. About how old is the universe, according to the Big Bang theory?
13.8 billion years
Evidence points to the universe beginning about 13.8 billion years ago.
33. What did astronomer Edwin Hubble discover about distant galaxies?
They are moving away from us, so the universe is expanding
Hubble showed distant galaxies are racing away from us, the key evidence that space is expanding.
34. Which famous constellation appears on the New Zealand flag?
The Southern Cross
The four red stars on our flag are the Southern Cross, Te Punga, visible all year from NZ.
35. What can the Southern Cross help you find at night?
South
Extend the long axis of the Cross about four and a half times and you are looking towards due south.
36. The bright 'evening star' or 'morning star' is usually not a star at all. What is it?
The planet Venus
Venus outshines every true star, appearing near the Sun at dusk or dawn.
37. Who was the first person to walk on the Moon, in 1969?
Neil Armstrong
Neil Armstrong stepped out first on the Apollo 11 mission, followed by Buzz Aldrin.
38. About how long does the International Space Station take to orbit Earth once?
90 minutes
The ISS zips around Earth roughly every 90 minutes, so its crew see 16 sunrises a day.
39. From where in New Zealand does Rocket Lab launch its Electron rockets?
Māhia Peninsula
Rocket Lab launches from Māhia Peninsula on the East Coast, one of the few private launch sites on Earth.
40. Which NZ region is famous as an International Dark Sky Reserve for stargazing?
Aoraki Mackenzie
The Aoraki Mackenzie reserve protects some of the darkest, clearest night skies in the world.
41. What is Matariki?
A star cluster whose rising marks the Māori New Year
Matariki is a star cluster, and its midwinter rising signals the Māori New Year in many traditions.
42. By what other name do astronomers know the Matariki cluster?
The Pleiades
Matariki is the Pleiades, known as the Seven Sisters in Greek stories and Subaru in Japan.
43. In the Matariki tradition, how many stars of the cluster are named and honoured?
Nine
Nine stars are honoured, including Matariki herself, Waitī, Waitā, and the wishing star Hiwa-i-te-rangi.
44. During Matariki, the star Pōhutukawa is connected with what?
Remembering those who have died in the past year
Pōhutukawa carries remembrance of loved ones lost since Matariki last rose, a gentle part of the celebration.
45. Some iwi mark the Māori New Year by a different star rising, because Matariki is hard to see from their area. Which star?
Puanga (Rigel)
Iwi in areas like Whanganui and Taranaki look to Puanga, showing how traditions differ around the motu.