PTE

unwanted artificial light that brightens the night sky and interferes with seeing celestial objects

a unit of distance equal to how far light travels in a vacuum in one year

relating to the Moon

an event in which the Moon passes partly or wholly through Earth's shadow

the apparent shape of the sunlit part of the Moon seen from Earth

a streak of light produced when a small object from space enters an atmosphere at high speed

a piece of material from space that survives passage through an atmosphere and reaches the ground

the ground-based team or center that monitors and directs a space mission

a facility equipped with instruments for observing objects and events in space

relating to an orbit or to motion along an orbit

relating to planets or their formation and behavior

to pass back from space into a planet's atmosphere

a mobile robotic vehicle used to explore the surface of a planet or moon

an event in which the Moon passes between Earth and the Sun and blocks part or all of the Sun from view

an uncrewed spacecraft sent to collect scientific information about space or celestial objects

a telescope placed in space to observe distant objects from outside Earth's atmosphere

to move or work outside a spacecraft while in space

all of space and time and the matter and energy within them

a long structural member that carries loads acting across its length, often by resisting bending

the temperature at which a liquid's vapor pressure equals the pressure acting on it, allowing boiling

likely to crack or break with little bending or permanent deformation

a structural member, usually upright, that carries loads mainly along its length in compression

to change from a gas or vapor into a liquid

to allow electric current to pass through a material

a material through which electric charge can move relatively easily

the mass of a material divided by the volume it occupies

able to return toward its original shape after a deforming force is removed, within its elastic limits

a physical property of matter that can be positive or negative and produces electrical interactions

an arrangement of connected electrical components that provides a path for electric current