Why is an absorption spectrum especially useful for astronomers? O It helped astronomers to understand the rainbows we see on Earth after storms
O It shows that the stars are transparent; we can see right through them
O It has bright lines in it which allow astronomers to determine how bright the star is
O It has dark lines in it that allow astronomers to determine what elements are in the
star

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

The plant food contains nh4)3po4 what tests would you run to verify the presence of the nh4 ion and the po4 ion

In november 1987, a massive iceberg broke loose from the antartic ice mass and floated free in the ocean. the chunk of ice was estimated to be 98 mi long, 25 mi wide, and 750 ft thick. a typical backyard swimming pool contains about 24,000 gallons of water. how many of these pools could you fill from the water in this iceberg? (assume the iceberg is a rectangular solid of the above dimensions and consists of water only). express answer in scientific notation.