Why does the solar nebula theory imply planets are common? a. Planets formed from the spiral arms of matter encountered around the Sun. Most main-sequence stars pass spiral arms dozens of times in their lives. b. Planets formed from the Sun’s past binary partner star. Binary systems with different masses and evolution rates are common. c. Planets formed from the envelope of the Sun, ejected at the time of hydrogen fusion ignition. Stars commonly eject their envelopes. d. Planets formed from the disk of gas and dust that surrounded the Sun, and such disks are common around young stars.

d. Planets formed from the disk of gas and dust that surrounded the Sun, and such disks are common around young stars.

Explanation:

A star passes through various stages before it becomes a full fledged star with its own planetary system. The same is with Sun as well. It was born out of a Nebula. Nebula is a cloud of dust and gases. The dust and gases start accumulating to form what we call as a protostar.

A lot of material at this stage is thrown out from the young star, this material forms a disk around the star. This disk is known as proto-planetary disk. The gases and dust of this disk then coalesce together to make planets and other objects of the star system.

We have observed such disks in the Orion nebula.

the part of the wave he is travelling on is the crest

where is the photo and the answer choices?