I mean what is walt's characteristics? Then maybe I can help
Answer:
The presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. ... On 11 February 2016, the LIGO collaboration announced the first direct detection of gravitational waves, which also represented the first observation of a black hole merger.
Explanation:
Option 2: Use the first word from that source as it is listed on the Works Cited page in parenthesis.
