Saturday, May 13, 2023

3998 - LISA - gravity wave observatory?

 

-    3998  -  LISA  -  gravity wave  observatory?     The first-time detection of Gravitational Waves (GW) by researchers at the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 triggered a revolution in astronomy. This phenomenon consists of ripples in spacetime caused by the merger of massive objects and was predicted a century prior by Einstein’s Theory of General Relativity


--------------  3998   -  LISA  -  gravity wave  observatory?

-    LISA will be a remarkable Gravitational-Wave Observatory and there is a way to make it 100 times more powerful?

-

-    With greater sensitivity, astronomers will be able to trace GW events back to their source and use them to probe the interiors of exotic objects and the laws of physics.

-

-    Since they were first detected by LIGO scientists in 2015, researchers with LIGO and other observatories worldwide have refined the types of GW events they can detect. This includes the Virgo Observatory in Italy (near Pisa) and the Kamioka Gravitational Wave Detector (KAGRA) in Hida, Japan.

-

-   There is no doubt that gravitational waves can be measured, astronomers want to use them as an additional source of information where previously only electromagnetic waves were available. Earth-based detectors, like LIGO/Virgo/Kagra are sensitive in the frequency range of tens of Hertz to several kilo-Hertz. This makes them sensitive to sources like black hole mergers of a few tens of solar masses.

-

-    However, it is known that much larger objects, like super-massive black holes (>10^6 solar masses), exist in the center of galaxies. Mergers of these objects produce gravitational waves far below the sensitive band of Earth-based detectors. To see them, we have to go to space and construct an observatory, like LISA, that has an arm length of 2.5 million km.

-

-    So far, astronomers have detected GW events caused by binary black holes (BBHs) or binary neutron stars (kilonova events), where the co-orbiting bodies eventually merged.

-

-    Studying these events could advance our understanding of the Universe. Among those are primordial gravitational waves that were produced during processes a fraction of a second after the Big Bang.  We hope that LISA can detect those.

-

-    LISA will observe a passing gravitational wave directly by measuring the tiny changes in distance between freely falling proof masses inside spacecraft with its high precision measurement system.

-

The basic idea of LISAmax is to detect GWs at even lower frequencies than what LISA can do. To be sensitive to these frequencies, one must increase the laser arms of the detector.

-

-    Larger arms mean larger wavelengths and, thus, lower frequencies.

The three LISAmax spacecraft are placed close to the triangular Lagrange points in the Sun-Earth system, which gives the detector an arm length of 259 million km. For comparison, LISA’s arms have a length of 2.5 million km. This makes LISAmax sensitive to GWs in the micro-Hertz band and opens a new window for GW astronomy.

-

-    Whatever source can be measured by LISA below 1 mHz, can be measured with LISAmax at a signal-to-noise ratio that is about two orders of magnitude better.

-

-    While LISA will only be able to see such sources shortly before the final merger event, LISAmax can observe these objects thousands of years before, thus allowing for a much better measurement.

-

-    The scientific community is investigating this concept, which could have drastic implications for the future of GW astronomy. In addition to expanding the range of GW events that could be detected, next-generation GW observatories can trace more events back to their sources.

-

-   The physics of the early Universe includes the study of primordial gravitational waves, which is also a major theme of the ESA’s Voyage 2050 program. By examining the GWs created during the inflationary epoch, scientists would finally be able to probe the physics and microphysics of this early cosmic period.

-

May 13, 2023            LISA  -  gravity wave  observatory?                3998                                                                                                                        

----------------------------------------------------------------------------------------

-----  Comments appreciated and Pass it on to whomever is interested. ---

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Saturday, May 13, 2023  ---------------------------------

-

 

 

 

 

         

 

 

No comments:

Post a Comment