The Science Missions of Columbia
Tools for Viewing The Universe
Tools for Viewing The Universe & Columbia Shuttle Added Corrective Optics to the Hubble Space Telescope
Hubble Discovers a New View of The Cosmos 2.2 billion light-years away The gravity of the cluster's trillion stars acts as a 2-million-light- year wide "lens" in space. This "gravitational lens" bends and magnifies the light of galaxies located far behind it, distorting their shapes and creating multiple images of individual galaxies.
The Chandra X-Ray Observatory The Chandra X-Ray Observatory
Chandra X-Ray Telescope: 1999 S. Chandrasekhar
Black Hole: Play The Movie When a star runs out of nuclear fuel, it will collapse. If the core of the star has a mass greater than 3 suns, no known nuclear forces can prevent the core from forming a deep gravitational warp in space called a BLACK HOLE Extremely dense stars with gravity so strong, not even light can escape A body passing by is deflected by its Grav. Field, if too close � Swallow Most galaxies believed to have Black holes at center
Milky Way's Central Black Hole : Sagittarius A* "We are getting a look at the everyday life of a Super massive black hole like never before,"
Binary Black Holes in NGC5240 (4x 10 8 Light Years away) Proof of two super massive black holes together in the same galaxy. These black holes are orbiting each other and will merge several hundred million years from now. The event will unleash intense radiation and gravitational waves and leave behind an even larger black hole than before. Simulation of Merger of Galaxies •NGC 6240 is a “starburst” galaxy: massive galaxy with star formation at exceptional rate due to recent collision & merger of smaller galaxies. •Dust and gas prevents optical/radio telescopes from peering in the central region but X-rays can penetrate gas/dust •Chandra saw Black holes surrounded by hot swirling vortices of matter called “accretion” disk � strong source of X-rays •In 10 8 years, two blackholes 3000 lightYears apart will collide and merge � Supermassive blackhole + radiation + gravity wave •Gravitational waves produce ripples in spacetime � minute change in distance between any two points •LISA on Space Shuttle hopes to catch such Gravity Waves
Farewell
Physics 2D Lecture Slides Feb 3 Vivek Sharma UCSD Physics
Quite Good !
The Universe Is Expanding : Hubble’s cosmological redshifts • Play the scenario backwards and forward • In the 1940s, based on Hubble’s Law, George Gamow proposed the universe began in a colossal explosion about 10 billion years ago – Based on experimental data (like we will see today) we now believe that Universe began as a singularity in spacetime • Where energy density and spacetime curvature were infinite – We don’t know what exactly happened between t=0 to t=10 -43 s » The radius of the universe was about 10 -52 cm » Temperature of the Universe was about 10 30 K – After that time (10 -35 s) the Universe has expanded & is well explained by known theories of (strong, weak, EM and Gravity) interactions » Temp = 10 28 � 10 16 K, universe is a hot quark-electron soup
History Of The Universe Since Origin
History of The Universe: Some Milestones
The farther we look into space, the farther back in time we are seeing.
Universe was hot opaque plasma in first 300K years 1K = 10 -4 eV
Universe was hot opaque plasma in first 300K years At t = 300,000 years, the universe was finally cool enough from its initial primordial fireball that electrons and protons could combine to form atoms (era of recombination)
Big Bang & Cosmic Microwave Radiation • The compact intense fireball of matter & radiation expanded, cooled, uderwent series of transitions at specific temps/time • Between 5 minutes to ≅ 100,000 years, universe consisted of plasma of H and He nuclei (and electrons) in thermal equilibrium with radiation • Once temperature fell below E=kT = 13.6 eV (B.E. of Hydrogen) – Hydrogen could form and not be broken up (like when things were hotter) – Now matter and radiation were decoupled and Universe became transparent • Radiation left behind (T = 3000K) could travel all over the Universe and continue to be Cosmologically red-shifted to longer and longer wavelengths • Observer today would expect this radiation to come from all sides and to have a radiation spectrum like a blackbody at 2.7K (dominant in Microwave Frequency) • Since then Gravity became dominant influence, density fluctuations led to formation of galaxies, stars etc
The Cosmic Microwave Radiation that fills all space is evidence of a hot Big Bang 1963:Bell Lab Horn Antenna detected a COBE Microwave signal from all parts of sky Nobel : Penzias & Wilson
What does the Cosmic Background Radiation Sound like ? Play MP3 audio file
The spectrum of the Cosmic Microwave Background Radiation reveals a temperature of 2.73K. Original Blackbody Spectrum @ T = 3000K modified to 3 o K by cosmological expansion
The microwave sky where variations are due to the motion of Earth through the cosmos Doppler Effect due to Earth’s motion The Universe is at 2.726K, Variation ∆ T= 0.0033K
Saw what light does, Now examine matter • Fundamental Characteristics of different forms of matter – Mass – Charge • Measurable � � � � –using some combination of E & B = + × F q E ( v B ) – Or E/B and some other macroscopic force e.g. Drag Force
Thomson’s Determination of e/m of Electron • In E Field alone, electron lands at D • In B field alone, electron lands at E • When E and B field adjusted to cancel Each other’s force � electron lands at F � e/m = 1.7588 x 10 11 C/Kg
Millikan’s Measurement of Electron Charge Find charge on oil drop is always in integral multiple of some Q Q e = 1.688 x 10 -19 Coulombs � M e = 9.1093 x 10 -31 Kg � Fundamental properties (finger print) of electron (similarly can measure proton properties etc)
Where are the electrons inside atoms? Early Thought: Plum pudding model � homogenous distribution of Positive charge with electrons embedded in them (atom is neutral)
Probing Inside an Atom with Alpha Particles
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