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Lecture# Modern Cosmology Basics

Description

This lecture covers the impact of COVID-19 on astronomy, the European Southern Observatory, ALMA radio interferometer, and the expression of distances in cosmology. It also delves into the Friedmann equations, the normalized Hubble parameter, and the challenges faced by ground-based observatories. The presentation explores the concept of dark energy, the equation of state, and the comoving distance in the context of modern cosmology.

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Related concepts (261)

Related lectures (209)

Cosmology is the study of the structure and evolution of the universe as a whole. This course describes the principal themes of cosmology, as seen
from the point of view of observations.

Key (cryptography)

A key in cryptography is a piece of information, usually a string of numbers or letters that are stored in a file, which, when processed through a cryptographic algorithm, can encode or decode cryptographic data. Based on the used method, the key can be different sizes and varieties, but in all cases, the strength of the encryption relies on the security of the key being maintained. A key's security strength is dependent on its algorithm, the size of the key, the generation of the key, and the process of key exchange.

Public-key cryptography

Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys. Each key pair consists of a public key and a corresponding private key. Key pairs are generated with cryptographic algorithms based on mathematical problems termed one-way functions. Security of public-key cryptography depends on keeping the private key secret; the public key can be openly distributed without compromising security.

Key exchange

Key exchange (also key establishment) is a method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm. If the sender and receiver wish to exchange encrypted messages, each must be equipped to encrypt messages to be sent and decrypt messages received. The nature of the equipping they require depends on the encryption technique they might use. If they use a code, both will require a copy of the same codebook. If they use a cipher, they will need appropriate keys.

Key size

In cryptography, key size, key length, or key space refer to the number of bits in a key used by a cryptographic algorithm (such as a cipher). Key length defines the upper-bound on an algorithm's security (i.e. a logarithmic measure of the fastest known attack against an algorithm), because the security of all algorithms can be violated by brute-force attacks. Ideally, the lower-bound on an algorithm's security is by design equal to the key length (that is, the algorithm's design does not detract from the degree of security inherent in the key length).

Key management

Key management refers to management of cryptographic keys in a cryptosystem. This includes dealing with the generation, exchange, storage, use, crypto-shredding (destruction) and replacement of keys. It includes cryptographic protocol design, key servers, user procedures, and other relevant protocols. Key management concerns keys at the user level, either between users or systems. This is in contrast to key scheduling, which typically refers to the internal handling of keys within the operation of a cipher.

Modern Cosmology: Observatories and Instruments

Explores the effects of COVID-19 on observatories, focusing on ESO and JWST.

The Matter Content in the Universe

Explores the matter content in the universe, including galaxy mass, dark matter relics, and the history of the universe.

Basics of Modern Cosmology - 2

Explores luminosity distance, the Einstein field equation, Stephen Hawking's contributions, and the cosmological principle, among other cosmological concepts.

Observable Universe: Contents and Properties

Explores the 3D distribution of galaxies, galaxy clustering, and the cosmic microwave background, shedding light on the observable universe's contents and properties.

Inhomogeneities in the Universe

Delves into gravitational instability, structures formation, and CMB temperature, exploring the inhomogeneities in the Universe.