Question

$\large\bold\red{WHAT \: IS DARK \: ENERGY }$​

Answer 1

ᴀɴsᴡᴇʀ:

ɪɴ ᴘʜʏsɪᴄᴀʟ ᴄᴏsᴍᴏʟᴏɢʏ ᴀɴᴅ ᴀsᴛʀᴏɴᴏᴍʏ, ᴅᴀʀᴋ ᴇɴᴇʀɢʏ ɪs ᴀɴ ᴜɴᴋɴᴏᴡɴ ғᴏʀᴍ ᴏғ ᴇɴᴇʀɢʏ ᴡʜɪᴄʜ ɪs ʜʏᴘᴏᴛʜᴇsɪᴢᴇᴅ ᴛᴏ ᴘᴇʀᴍᴇᴀᴛᴇ ᴀʟʟ ᴏғ sᴘᴀᴄᴇ, ᴛᴇɴᴅɪɴɢ ᴛᴏ ᴀᴄᴄᴇʟᴇʀᴀᴛᴇ ᴛʜᴇ ᴇxᴘᴀɴsɪᴏɴ ᴏғ ᴛʜᴇ ᴜɴɪᴠᴇʀsᴇ. ... ᴛʜᴇ ᴅᴇɴsɪᴛʏ ᴏғ ᴅᴀʀᴋ ᴇɴᴇʀɢʏ ɪs ᴠᴇʀʏ ʟᴏᴡ (~ 7 × 10−30 ɢ/ᴄᴍ3), ᴍᴜᴄʜ ʟᴇss ᴛʜᴀɴ ᴛʜᴇ ᴅᴇɴsɪᴛʏ ᴏғ ᴏʀᴅɪɴᴀʀʏ ᴍᴀᴛᴛᴇʀ ᴏʀ ᴅᴀʀᴋ ᴍᴀᴛᴛᴇʀ ᴡɪᴛʜɪɴ ɢᴀʟᴀxɪᴇs.

Answer 2

$\large\bold\red{WHAT\:IS DARK\:ENERGY }$