Hubble's observations indicated that the jet was
traveling at a speed that was seven times the speed of light.
Later radio readings showed that the jet had slowed
to four times the speed of light. This is a "cosmic illusion,"
however since nothing moves more quickly than light.
A jet was blasted across space at 99.97% the speed
of light by the collision of two neutron stars. NASA measurements from the
Hubble Space Telescope support this.
In August 2017, the explosive event known as
GW170817 took place. The explosion's energy was compared to that of a supernova
explosion.
The binary neutron star merging resulted in the
simultaneous detection of the first gravitational wave and gamma-ray signals.
This series of bizarre accidents marked a turning point in the inquiry.
The effects of this merger were seen by 70
observatories on Earth and in space. They also found a variety of
electromagnetic radiation, in addition to gravitational waves. This incident
took place in 2017.
A Historical Remark
In terms of time domain and multi-messenger
astrophysics, this was a huge accomplishment. the examination of the universe's
long-term evolution using different "messengers" including light and
gravitational waves.
Scientists pointed Hubble towards the explosion
location two days after it occurred. A black hole was produced by the collision
of two neutron stars, and its gravitational pull attracted material. From the
poles, jets shot out of a quickly rotating disc.
During the explosion, the screaming aircraft slammed
into the growing debris cloud and scooped everything up. Finally, a material
blob gave way to an emerging jet.
This comprehensive picture was produced after years
of analysis of Hubble data as well as data from other telescopes.
Hubble images were merged with views from other
National Science Foundation radio observatories for extremely long baseline
interferometry (VLBI). 75 and 230 days after the incident, data were collected.
According to Kunal P. Mooley of Caltech in Pasadena,
California, "I'm amazed that Hubble could offer us with such a precise
measurement, which approaches the accuracy reached by large radio VLBI
observatories distributed throughout the globe." On October 13th, a study
with him as the primary author will appear in Nature.
Extensive Precision
The scientists also merged Hubble data with
information from the Gaia satellite and VLBI in order to produce very precise
results. This measurement was made, according to Jay Anderson of the Space
Telescope Science Institute in Baltimore, Maryland, following months of
meticulous data processing.
They were able to find the explosion location
because to their combined observations. Hubble's observations indicated that
the jet was traveling at a speed that was seven times the speed of light. Later
radio readings showed that the jet had slowed to four times the speed of light.
Since nothing can travel faster than light, this
so-called "superluminal" movement is an illusion. The light the jet
releases subsequently will travel a shorter distance since it is approaching
Earth at a speed that is almost equal to the speed of light.
In essence, the jet follows its own light. Because
of this, the jet's light was released considerably later than the observer
anticipated. The object's speed is thus overstated and is greater than the
speed of light.
Wenbin Lu of the University of California, Berkeley
estimates that the jet was traveling at 99.97% the speed of light at the moment
of launch.
The hypothesis that neutron star mergers are
connected to brief gamma-ray bursts is supported by a 2018 report of a
combination of Hubble and VLBI observations. A fast-moving jet that is
developing, as seen in GW170817, is necessary for this relationship.
Hubble's constant
Additionally, this study permits more thorough
investigations of neutron star mergers discovered by LIGO, Virgo, and KAGRA's
gravitational wave detectors.
A sufficient sample of relativistic jets might
eventually provide a different way to measure the Hubble constant. This
constant is an approximation of the universe's expansion rate.
For the early universe and the nearby universe, the
Hubble constant values are different. One of the biggest puzzles in
astrophysics is this.
Exceptionally accurate observations of Type Ia supernovae by Hubble and other observatories, as well as measurements of the Cosmic Microwave Background by the Planck spacecraft, form the foundation for differences in values. Astronomers may be able to answer the mystery with a better knowledge of relativistic jets.