- 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.
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- 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.
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May 13, 2023 LISA -
gravity wave observatory? 3998
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--------------------- --- Saturday, May 13, 2023
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