Analyzing the Light: Redshift and Blueshift of RBH-1

The runaway black hole RBH-1 presents a complex and fascinating case for the measurement of redshift and blueshift. It exhibits both phenomena simultaneously, depending on the specific part of its structure that is being observed. This is a direct result of its high-speed motion and its immense distance from Earth.

Detailed Breakdown of the Spectral Shifts

1. Blueshift: The "Bow Shock" Front

Observation Point: The dense wall of gas directly in front of the black hole, which it pushes through space like a ship's bow wave.

Cause & Type of Shift: This gas is being compressed and pushed directly toward Earth by the black hole's forward velocity of approximately 1,000 km/s. This motion creates a Doppler Blueshift, where light waves are compressed to shorter (bluer) wavelengths.

2. Redshift: The Sides of the Bow Shock

Observation Point: The gas streaming around the outer edges of the bow shock.

Cause & Type of Shift: As the black hole plows forward, it displaces material sideways and backward, away from our line of sight. This motion of gas away from Earth results in a Doppler Redshift, stretching the light to longer (redder) wavelengths.

3. Strong Redshift: The Host Galaxy

Observation Point: The black hole's original host galaxy, located approximately 7.5 to 9 billion light-years away.

Cause & Type of Shift: The dominant signal here is a powerful Cosmological Redshift. This redshift is not primarily from the galaxy's own motion but from the stretching of space itself over the vast distance the light has traveled to reach us.

Summary of Spectral Observations

Observed Region	Shift Type	Primary Cause
Bow Shock Front	Blueshift	Direct motion toward Earth from high-speed travel
Bow Shock Sides	Redshift	Gas displaced sideways/backward, moving away from Earth
Host Galaxy	Strong Redshift	Expansion of the universe over billions of light-years

The Science Behind the Shifts: These measurements are based on the Doppler effect, the same principle that changes the pitch of a passing siren. For light, motion toward an observer compresses waves (blueshift), while motion away stretches them (redshift). In cosmology, the expansion of the universe causes a dominant redshift for all extremely distant objects.

For RBH-1, astronomers used instruments like the James Webb Space Telescope's NIRSpec to precisely measure these different shifts in light from various parts of the system, allowing them to map its complex motion and confirm its nature as a runaway black hole.