Cosmology and Cosmic Microwave Background Quiz

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Questions and Answers

What is the approximate temperature of the Cosmic Microwave Background (CMB)?

0 K

Billions of degrees Kelvin

3000 K

2.7 K (correct)

What is the primary cause of the cosmological redshift?

The cooling of the Universe.

The Doppler effect.

The expansion of space itself. (correct)

The gravitational pull of massive objects.

The CMB is considered evidence of what cosmological event?

The formation of stars.

The end of the Dark Ages.

The inflation phase of the universe.

The Big Bang. (correct)

During which phase did the Universe's temperature cool enough for hydrogen to recombine?

When the temperature reached around 3000 K. (A) Signup and view all the answers

Before the recombination of hydrogen, what state was the matter of the universe in?

A highly energetic and chaotic ionized plasma. (D) Signup and view all the answers

What was the initial temperature of the Universe, according to the text, just before the formation of the CMB?

Billions of degrees Kelvin. (C) Signup and view all the answers

Who first observed the cosmological redshift?

Penzias and Wilson. (C) Signup and view all the answers

What fundamental characteristic of the Universe resulted in the observed temperature of the CMB being so much lower than the initial temperature?

The expansion of space. (D) Signup and view all the answers

What does the abundance of deuterium tell us about the composition of ordinary matter in the universe?

Ordinary matter contributes less than 5% of the critical density. (A) Signup and view all the answers

Which of the following best describes Weakly Interacting Massive Particles (WIMPs)?

They are predicted particles that do not participate much in nuclear reactions. (C) Signup and view all the answers

What significant measurement was achieved by the COBE mission regarding the CMB spectrum?

It confirmed the spectrum is nearly a perfect black body at 2.74K. (A) Signup and view all the answers

What is the primary reason why WIMPs are difficult to detect?

They interact very rarely with other matter. (B) Signup and view all the answers

Which space mission provided the scientific community with increased spatial resolution measurements of the CMB temperature fluctuations?

WMAP (D) Signup and view all the answers

What technology, suggested in the 1960s, became feasible for astronomers to use for observation?

Interferometry. (A) Signup and view all the answers

What was a key contribution of the Planck mission to the study of CMB?

It provided better angular resolution in mapping the CMB. (D) Signup and view all the answers

Based on the content, what is the approximate percentage of dark matter in the universe?

25% (C) Signup and view all the answers

According to measurements from space missions, what is the approximate ratio between Dark Energy and Dark Matter density in the universe?

7:3 (D) Signup and view all the answers

What did the Wilkinson Microwave Anisotropy Probe (WMAP) primarily measure?

The fluctuations of the cosmic microwave background and the densities of baryonic and non-baryonic matter. (B) Signup and view all the answers

What is the approximate ratio between Dark Energy, Cold Dark Matter, and Baryonic matter, according to the measurements of space missions?

25:5:1 (A) Signup and view all the answers

According to the content, which is the largest constituent of the universe?

Dark matter. (B) Signup and view all the answers

What does 'redshift at decoupling' refer to, as constrained by measurements of the CMB?

The time when photons ceased interacting with charged particles and began to travel freely. (B) Signup and view all the answers

What is the primary method of research used by scientists to investigate dark matter?

Searching for dark matter through other means like particle physics experiments. (D) Signup and view all the answers

What is the main concept behind Einstein's theory of general relativity that supports the existence of gravitational waves?

Massive accelerating objects disrupt space-time, creating ripples. (A) Signup and view all the answers

What type of event is NOT mentioned as a potential source of strong gravitational waves?

Lunar tides (B) Signup and view all the answers

Which type of celestial object is NOT typically associated with the emission of high-energy radiation like X-rays?

Planetary Nebulae (B) Signup and view all the answers

What is the primary mechanism by which black holes emit X-rays?

Accretion of matter from nearby stars, causing heating due to friction (C) Signup and view all the answers

What is the cosmic X-ray background primarily composed of?

Diffused radiation from a variety of universe-wide sources (A) Signup and view all the answers

Which of the following best describes thermal bremsstrahlung?

X-ray radiation emitted by hot gas where electrons interact with ions (A) Signup and view all the answers

What causes the regular pulses of X-rays emitted by some neutron stars?

The sweeping of their magnetic poles across our line of sight (C) Signup and view all the answers

What distinguishes an X-ray binary from other X-ray sources?

They involve a normal star and a compact object in orbit around each other (C) Signup and view all the answers

Besides X-rays, what is another type of high-energy radiation commonly studied in high-energy astronomy?

Gamma rays (D) Signup and view all the answers

Which component of the Sun is a significant source of X-rays in our solar system?

Solar corona (B) Signup and view all the answers

What causes the corona to emit X-rays?

The extremely high temperatures present. (A) Signup and view all the answers

What is a key characteristic of an X-ray binary system?

It involves a normal star and a compact stellar remnant. (A) Signup and view all the answers

What is the mechanism that produces X-rays in an X-ray binary?

The heating of material as it falls into the primary star via an accretion disc. (C) Signup and view all the answers

What are the two main subcategories of X-ray binaries?

High Mass X-ray Binary (HMXB) and Low Mass X-ray Binary (LMXB). (C) Signup and view all the answers

What was the primary purpose of the VELA satellites that first detected Gamma-ray bursts?

Detecting nuclear detonations in space. (A) Signup and view all the answers

What is the primary difference between long-duration and short-duration gamma-ray bursts?

Their association with different cosmic events. (B) Signup and view all the answers

What role does the detection of gravitational waves play in studying gamma-ray bursts?

It enables astronomers to precisely locate the source of short-duration GRBs associated with compact object mergers. (D) Signup and view all the answers

What technique did the VELA satellites use to locate the source of gamma-ray bursts?

Triangulation based on the arrival time at multiple satellites. (D) Signup and view all the answers

What is the main purpose of optical telescopes in the context of gamma ray burst (GRB) events?

To identify and study the bright source that appears after a GRB detection. (A) Signup and view all the answers

What is the primary goal of the Gaia mission?

To create a detailed 3D map of the Milky Way galaxy. (C) Signup and view all the answers

Why is there a plan to develop a successor to the Gaia mission that would operate in the infrared spectrum?

To observe past the gas and dust clouds obscuring optical views. (C) Signup and view all the answers

What is the James Webb Space Telescope's (JWST) overarching scientific goal?

To investigate the origins of the Universe and our place in it. (B) Signup and view all the answers

What is the significance of the JWST transit curve observation of WASP 39-b?

It showed the presence of carbon monoxide (CO) and the possibility of liquid water oceans. (D) Signup and view all the answers

What does the term 'puffy' gas giant, as applied to WASP 39-b, indicate?

It is a gas planet that is larger in radius than expected for its mass. (A) Signup and view all the answers

How is the James Webb Space Telescope communication with the public?

Through carefully presented results with images, and with involvement of scientists, journalists, and artists. (B) Signup and view all the answers

What can be inferred from the fact that some Nobel Prizes have been awarded for space-related discoveries?

Space exploration has led to groundbreaking scientific advancements that are worthy of the highest recognition. (A) Signup and view all the answers

Study Notes

Fundamental (Astro) Physics Breakthroughs Enabled by Space

This chapter details how space-based observations advance astrophysical understanding.
Earth's atmosphere limits observations at specific wavelengths and impacts signal-to-noise ratios due to atmospheric absorption.
Two fundamental theoretical challenges addressed through space observations are detailed in sections 5.1 and 5.2.
Hubble Space Telescope (HST), GAIA mission, and James Webb Space Telescope (JWST) are introduced in sections 5.5, 5.8, and 5.9, along with their groundbreaking discoveries.
An overview of Nobel prizes related to space studies is in section 5.10.

The Cosmic Microwave Background: Evidence of the Big Bang

The Cosmic Microwave Background (CMB) is a nearly uniform microwave radiation pervading the universe.
Its temperature is approximately 2.7 Kelvin, resembling blackbody emission.
The CMB is considered the afterglow of the Big Bang.
The Big Bang theory proposes an exceptionally hot, dense initial point that expanded, eventually cooling down to allow hydrogen recombination and photon escape from plasma.
The CMB provides a nearly homogeneous "fingerprint" of the early hot universe due to this expansion and cooling.
Cosmological redshift is the observed elongation of photon wavelengths from astronomical objects due to their movement away from an observer.
This shift is linked to the Doppler effect, which explains observed frequency or wavelength changes in objects moving towards or away from an observer.
Penzias and Wilson's 1964 accidental discovery of CMB, which earned them a Nobel Prize in 1978, was during telecommunications experiments.
The COBE (COsmic Background Explorer) mission (1992) measured CMB spectrum, revealing a near-perfect blackbody spectrum at 2.74 Kelvin and minimal deviations from isotropy (uniformity) in intensity distribution.
The WMAP (Wilkinson Microwave Anisotropy Probe) mission (2002) enhanced spatial resolution of CMB temperature fluctuations data.
The Planck mission (2009) provided detailed high-resolution maps, enabling constraints on cosmological parameters like:
- Dark Energy to Dark Matter density ratio (~7:3)
- Dark Energy, Cold Dark Matter, and Baryonic Matter density ratio (~25:5:1)
- Redshift at decoupling (~1060)

Gravitational Waves

Gravitational waves are ripples in spacetime caused by violent universe events like merging black holes or neutron stars exploding.
Albert Einstein predicted their existence in 1916.
High-energy events like black hole collisions produce the strongest gravitational waves
Interferometers are required to measure incredibly small changes in spacetime to detect these waves.
The layout of a basic Michelson interferometer (crucial for detecting gravitational waves) is based on a laser, beam splitter, and mirrors.

Dark Matter

Dark matter cannot be observed directly, because it doesn't emit light and interacts weakly with ordinary matter.
Its composition is not ordinary matter, such as black holes, planets, or dim stars.
WIMP (weakly interacting massive particles) are a hypothesized type of elementary particle accounting for a significant portion of the universe's dark matter.
It doesn't participate in nuclear reactions and its exact properties remain unknown.

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Description

Test your knowledge on the Cosmic Microwave Background (CMB) and related cosmological concepts. This quiz covers fundamental questions about the universe's temperature, its early state, and major discoveries such as the cosmological redshift and WIMPs. Perfect for students of cosmology or anyone interested in the origins of our universe.