Einstein’s Telescope: Gravitational Lensing Explained Quiz

If mass causes the fabric of spacetime to curve, and if light travels along the curves of space, then a massive object will redirect light from a distant source toward an observer, behaving like a glass lens.

If gravity affects the geometry of space itself as part of space relativity basics, then light will follow a curved path even in a complete vacuum when it passes near any object with sufficient mass.

If a gravitational lens focuses light from a distant background object toward Earth, and if focusing light increases the apparent size and brightness of that object, then we can see distant galaxies that would be invisible to normal telescopes.

If a massive object is positioned between Earth and a faint, distant target, then the gravitational effect will brighten the target; therefore, the primary use of this effect is for observing distant objects.

If the theory of General Relativity predicts that mass warps the dimensions of spacetime, and if Albert Einstein developed this theory in the early 20th century, then he is the scientist responsible for these basics.

If gravitational lensing is caused by mass, and if stars, galaxies, and black holes all possess significant mass, then they can all bend light; if an asteroid has very little mass, its effect is too small to be used as a lens.

If light from a background source travels along several different curved paths around a massive lens to reach the same observer, then the observer will perceive the source appearing in multiple locations at once.

If a gravitational lens is not perfectly symmetrical or aligned, then the light being focused will be distorted; if the light is distorted as it is magnified, it appears as long, glowing arcs or a circular ring in telescope images.

If the alignment of the background source and the foreground lens is perfectly symmetrical, then the light is bent equally in all directions; if this happens, the result is a full circle known as an Einstein Ring.

If a galaxy cluster contains a massive amount of matter, and if more matter creates a stronger gravitational lens, then the cluster acts like a massive magnifying glass that brightens the light from objects far behind it.

If the speed of light in a vacuum (c) is a universal constant, and if gravity only changes the "shape" of the path the light takes, then the light continues to travel at approximately 3 * 10^8 m/s regardless of the bend.

If the lens is the foreground object that bends the light, and if lensing requires light to be bent from somewhere, then the background object whose light is being affected is defined as the source.

If the gravitational lens concentrates light that would otherwise have missed the Earth, then the object appears brighter; this specific increase in brightness is called magnification.

If lensing is a geometric alignment, then you must have something to provide the light, something heavy to bend the light, and someone at the end of the path to see the result.

If we observe a significant amount of light bending in a region of space but see very little visible light from stars, then there must be invisible mass (Dark Matter) providing the gravity necessary for that lensing.

If gravitational lensing relies on the force of gravity to warp space rather than the refraction of light through a physical medium, then any massive object—transparent or opaque—can act as a lens.

If General Relativity describes gravity as a geometric property of the universe, and if mass distorts that geometry, then the specific thing being warped is the four-dimensional fabric of spacetime.

If mass curves the dimensions of space, and if a photon always takes the shortest possible path through space, then the "straightest" path through a curved region is actually a curved trajectory from our perspective.

If light is bent and focused by gravity, it can be distorted into various shapes depending on alignment; if the alignment is offset, you see arcs or multiple dots; if it is perfect, you see a ring.

If a planet orbits a lens star, it adds its own gravity to the lensing effect; if this causes a tiny extra spike in brightness (microlensing), then astronomers can use this to detect planets in other parts of the galaxy.