The Laser Interferometer erdvė Antenna (LISA) mission has received the go ahead of European erdvė Agency (ESA). This paves the way for developing the instruments and spacecrafts commencing January 2025. The mission is led by ESA and is a result of collaboration between ESA, its Member State erdvė agencies, NASA, and an international consortium of scientists.
Scheduled to be launched in 2035, LISA will be the first erdvėPagrindu gravitacinė banga observatory dedicated to detection and study of millihertz ripples caused by distortions in the fabric of erdvė-laikas (gravitacinės bangos) across the visata.
Unlike the ground based gravitacinė banga detectors (LIGO, VIRGO, KAGRA, and LIGO India) which detect gravitacinės bangos in frequency range of 10 Hz to 1000 Hz, LISA will be designed to detect gravitacinės bangos of much longer wavelengths in the low frequency range between 0.1 mHz and 1 Hz.
Itin žemo dažnio (10-9-10-8 Hz) gravitacinės bangos (GWs) with wavelengths from weeks to years from supermassive binary Juodosios skylės can be detected using ground-based Pulsaro laiko matricos (PTA). However, low frequency gravitacinės bangos (GWs) with frequency between 0.1 mHz and 1 Hz can neither be detected by LIGO nor by Pulsar Timing Arrays (PTAs) – the wavelength of these GWs is too long for LIGO and too short for PTAs to detect. Hence, the need for erdvė-based GW detector.
LISA will be a constellation of three spacecrafts in accurate equilateral triangle formation in space. Each side of the triangle will be 2.5 million km long. This formation (of the three spacecrafts) will orbita Sun in an Earth-trailing heliocentric orbita between 50 and 65 million km from Earth while maintaining a mean inter-spacecraft separation distance of 2.5 million km. This space-based configuration makes LISA an extremely large detector to study low frequency gravitacinės bangos that ground-based detectors can not.
For detection of GWs, LISA will use pairs of test masses (solid gold-platinum cubes) free-floating in special chambers at the heart of each spacecraft. Gravitacinis ripples will make extremely small changes in the distances between test masses in the spacecrafts which will be measured through laser interferometry. As demonstrated by LISA Pathfinder mission, this technology is capable of measuring changes in distances to a few billionths of a millimetre.
LISA will detect GWs caused by merger of supermassive Juodosios skylės at the centre of galaxies thus will shed light on evolution of galaxies. The mission should also detect the predicted gravitational "skambėti" susiformavo pradiniais momentais visata pirmosiomis sekundėmis po didžiojo sprogimo.
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Nuorodos:
- ESA. Naujienos – Erdvės laiko bangos fiksavimas: LISA pradeda veikti. Paskelbta 25 m. sausio 2024 d https://www.esa.int/Science_Exploration/Space_Science/Capturing_the_ripples_of_spacetime_LISA_gets_go-ahead
- NASA. LISA. Galimas adresu https://lisa.nasa.gov/
- Pau Amaro-Seoane et al. 2017. Laser Interferometer erdvė Antenna. Preprint arXiv. DOI: https://doi.org/10.48550/arXiv.1702.00786
- Baker et al. 2019. The Laser Interferometer erdvė Antenna: Unveiling the Millihertz Gravitational Wave Sky. Preprint arXiv. DOI: https://doi.org/10.48550/arXiv.1907.06482
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