1.
What does LIGO stand for?
Correct Answer
B. Laser Interferometer Gravitational-wave Observatory
Explanation
LIGO stands for Laser Interferometer Gravitational-wave Observatory. It is a scientific collaboration and observatory dedicated to the detection of gravitational waves—ripples in spacetime caused by the acceleration of massive objects, such as the collision of black holes or neutron stars.
2.
When was the first direct detection of gravitational waves made by LIGO?
Correct Answer
B. September 14, 2015
Explanation
The first direct detection of gravitational waves by LIGO (Laser Interferometer Gravitational-Wave Observatory) was made on September 14, 2015. This historic discovery marked a significant milestone in astrophysics and confirmed the existence of gravitational waves, as predicted by Albert Einstein's theory of general relativity.
3.
What is the main working principle of LIGO?
Correct Answer
B. Gravitational wave detection
Explanation
The main working principle of LIGO (Laser Interferometer Gravitational-Wave Observatory) is Gravitational wave detection. LIGO is specifically designed to detect and measure gravitational waves, which are ripples in spacetime caused by the acceleration of massive objects, such as the collision of black holes or neutron stars. It does so using laser interferometry to measure the minute changes in distance between mirrors caused by passing gravitational waves, allowing for their direct observation and the study of cataclysmic cosmic events.
4.
Which scientist first predicted the existence of gravitational waves?
Correct Answer
B. Albert Einstein
Explanation
The scientist who first predicted the existence of gravitational waves was Albert Einstein. In 1916, Albert Einstein published his theory of general relativity, which included equations that described the existence of gravitational waves as a consequence of the way massive objects warp spacetime. It took many decades, but the direct detection of gravitational waves, as predicted by Einstein's theory, was eventually achieved by experiments such as LIGO (Laser Interferometer Gravitational-Wave Observatory) in 2015.
5.
How many LIGO detectors are currently in operation as of 2023?
Correct Answer
B. 2
Explanation
There are currently two LIGO detectors in operation, one located in Livingston, Louisiana, and the other in Hanford, Washington.
6.
What is the shape of the interferometer used in the LIGO detectors?
Correct Answer
C. Linear
Explanation
The interferometer used in the LIGO (Laser Interferometer Gravitational-Wave Observatory) detectors is linear in shape. LIGO consists of two L-shaped interferometers, each with two long, straight arms that intersect at right angles. This design allows LIGO to precisely measure changes in the lengths of its arms when gravitational waves pass through, providing a powerful tool for detecting and studying these cosmic phenomena.
7.
What is the approximate length of the LIGO arms?
Correct Answer
B. 4 kilometers
Explanation
The approximate length of the LIGO (Laser Interferometer Gravitational-Wave Observatory) arms is 4 kilometers (about 2.5 miles) for each arm. LIGO has two detectors located in Livingston, Louisiana, and Hanford, Washington, both of which have arms of this length. These long arms are essential for the precise measurement of gravitational waves as they cause minute changes in the length of the arms when they pass through.
8.
What is the frequency range of gravitational waves detected by LIGO?
Correct Answer
D. Hertz
Explanation
LIGO (Laser Interferometer Gravitational-Wave Observatory) is designed to detect gravitational waves within a specific frequency range. The frequency range of gravitational waves detected by LIGO typically falls within the range of 10 Hertz (Hz) to a few thousand Hertz (Hz). This frequency range corresponds to gravitational waves generated by violent cosmic events, such as the mergers of black holes or neutron stars, which produce rapid oscillations in spacetime that fall within this frequency range. Gravitational waves from other sources, such as those associated with the early universe, would have much lower frequencies and are not detectable by LIGO.
9.
Which celestial event was the source of the first observed gravitational waves?
Correct Answer
C. Black hole merger
Explanation
The source of the first observed gravitational waves was the merger of two black holes. This historic event, known as GW150914, was detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) on September 14, 2015. It marked the first direct observation of gravitational waves and confirmed a key prediction of Albert Einstein's theory of general relativity. The collision of the two black holes produced a violent and cataclysmic event that sent gravitational waves rippling through spacetime, and LIGO's detectors in Livingston, Louisiana, and Hanford, Washington, successfully detected these waves.
10.
What is the main purpose of the Virgo detector in Italy?
Correct Answer
C. Gravitational wave detection
Explanation
The main purpose of the Virgo detector in Italy is Gravitational wave detection. Like the LIGO (Laser Interferometer Gravitational-Wave Observatory) detectors in the United States, Virgo is also a gravitational wave observatory. It is designed to detect and study gravitational waves, such as those produced by the collisions of black holes and neutron stars, through precise measurements using laser interferometry. Virgo works in collaboration with LIGO to enhance the global network of gravitational wave detectors and improve the accuracy of gravitational wave detections.
11.
What is the sensitivity range of LIGO detectors?
Correct Answer
D. Subatomic scale
Explanation
The sensitivity range of LIGO (Laser Interferometer Gravitational-Wave Observatory) detectors is on the subatomic scale. LIGO's detectors are incredibly sensitive and can measure changes in distance that are on the order of a fraction of the diameter of an atomic nucleus. This level of precision is necessary to detect the tiny distortions in spacetime caused by the passage of gravitational waves, which originate from massive cosmic events, such as the mergers of black holes or neutron stars.
12.
Which Nobel Prize did the scientists involved in LIGO's first detection of gravitational waves receive and in which year?
Correct Answer
A. Nobel Prize in pHysics, 2017
Explanation
The scientists involved in LIGO's first detection of gravitational waves were awarded the Nobel Prize in Physics in the year 2017 for their groundbreaking work. This prestigious recognition was a testament to the significance of their discovery, which confirmed a key prediction of Albert Einstein's theory of general relativity and opened a new era in astrophysics and our understanding of the universe.
13.
What is the name of the upcoming space-based gravitational wave observatory by NASA called?
Correct Answer
A. LISA
Explanation
The upcoming space-based gravitational wave observatory by NASA is called "LISA" (Laser Interferometer Space Antenna). LISA is designed to observe gravitational waves from space and is a collaborative project involving NASA and the European Space Agency (ESA). It is expected to provide a new perspective on the universe and complement the ground-based detectors like LIGO and Virgo.
14.
What is the expected frequency range of gravitational waves detected by LISA?
Correct Answer
D. Millihertz
Explanation
The expected frequency range of gravitational waves detected by LISA (Laser Interferometer Space Antenna) is typically in the range of millihertz (mHz). LISA is designed to observe lower-frequency gravitational waves compared to ground-based detectors like LIGO. This frequency range is associated with sources of gravitational waves, such as massive black hole mergers, that produce slower oscillations in spacetime over longer periods.
15.
What is the next-generation ground-based gravitational wave observatory under development by LIGO called?
Correct Answer
D. LIGO Voyager
Explanation
The next-generation ground-based gravitational wave observatory under development by LIGO (Laser Interferometer Gravitational-Wave Observatory) is called "LIGO Voyager." LIGO Voyager represents an upgraded and advanced version of the existing LIGO detectors, with improved sensitivity and capabilities for detecting gravitational waves from distant cosmic events. It aims to further enhance our ability to observe and study these elusive phenomena in the universe.