Puzzle

Across

5. Type of telescope that uses mirrors instead of lenses to collect light
6. The minimum speed a body must reach to break free from a planet's gravitational field
9. The outermost layer of the Sun's atmosphere, visible during a solar eclipse
15. The length from lens or mirror to the point where light converges to a sharp image
16. Visible surface layer of the Sun from which light is emitted into space
19. Thermodynamic measure of disorder; the universe continuously moves toward higher entropy
21. Nearest major galaxy to the Milky Way, also the name of a constellation
22. Scale used to measure the brightness of stars, where lower numbers mean brighter objects
25. Phenomenon where light from receding galaxies shifts toward longer wavelengths
27. Rapid exponential expansion of the universe in its first fraction of a second
29. Space telescope launched in 1990, named after an astronomer
32. Orbit at ∼36,000 km where a satellite matches Earth's rotation and appears stationary
33. Zodiacal constellation of the bull, containing the Pleiades and the Crab Nebula
37. Rapidly rotating neutron star that emits regular radio pulses
38. Type of telescope that detects long-wavelength electromagnetic radiation from space
39. The diameter of a telescope's main lens or mirror, determining light-gathering ability
42. Rocket design using sequential sections that drop away as fuel is consumed
43. Theoretical tunnel through spacetime connecting two distant regions of the universe
44. Theory proposing that fundamental particles are one-dimensional vibrating filaments
45. Optics system in modern telescopes that corrects for atmospheric distortion in real time
46. Chemical reaction between fuel and oxidizer that releases the energy powering a rocket
47. Ultra-dense collapsed stellar remnant composed almost entirely of neutrons
48. Mysterious force causing the accelerating expansion of the universe

Down

1. Band on the Hertzsprung-Russell diagram where stable hydrogen-burning stars reside
2. The cargo or satellite a rocket carries into space
3. The force produced by a rocket engine pushing it forward
4. Combined term for the fuel and oxidizer mixture that a rocket engine burns
7. Massive stellar explosion marking the death of a large star
8. The theoretical origin event of the universe (∼14 billion years ago)
9. Variable star used as a 'standard candle' to measure cosmic distances
10. Famous hunter constellation containing the bright stars Betelgeuse and Rigel
11. Type of telescope that uses lenses to bend and focus light
12. Technique of splitting light into its spectrum to identify elements in stars
13. The point in the sky directly overhead, often the optimal direction for telescope observation
14. Microwave background radiation: the 'afterglow' of the Big Bang permeating all of space
17. Phase when a spacecraft returns through the atmosphere, generating intense heat
18. Apparent shift of a nearby star's position used to measure stellar distances
20. Chemical that provides oxygen to combust rocket fuel in the vacuum of space
23. Extremely luminous active galactic nucleus powered by a supermassive black hole
24. Prefix of the Great and Little Bear constellations containing Polaris
26. Point of infinite density at the centre of a black hole where known physics breaks down
28. Small northern constellation containing Vega, one of the brightest stars in the sky
29. Large constellation in the northern sky representing the mythological hero
30. Unit of astronomical distance equal to about 3.26 light-years, derived from parallax
31. W-shaped constellation in the northern sky named after a queen of Ethiopian mythology
34. The point in an orbit closest to the Sun
35. Optical aberration causing stars near the edge of a telescope's field to appear comet-like
36. Invisible mass-bearing substance that does not emit or absorb light, detected only by gravity
40. Shaped exhaust outlet that accelerates hot gases to maximise rocket thrust
41. Southern constellation of the sail, part of the ancient ship Argo grouping