The Square Kilometre Array and Radio Astronomy: Canada & Australia Kevin Vinsen (ICRAR, UWA)
Spot Quizzes / Guess Tests I have some fun spot quizzes just to highlight how big some numbers are. ICRAR � 2
Scientific Notation I promised no hard maths, but you need to understand the numbers I use. Astronomy deals with very large and very small numbers… 1.5x10 11 meters Distance from Earth to Sun ~ 150 000 000 000 meters 1.67x10 -27 kg Mass of hydrogen atom ~ 0.000 000 000 000 000 000 000 000 001 67 kg ICRAR � 4
Number Scales A lot of this presentation is about really BIG numbers. Here’s a reminder of the SI Units: 10 n Prefix Symbol Decimal Short Example 10 6 mega M 1,000,000 Million 3 billion base pairs in the human 10 9 giga G 1,000,000,000 Billion genome 10 12 tera T 1,000,000,000,000 Trillion 1 ly = 9.460 tera kilometers 10 15 peta P 1,000,000,000,000,000 Quadrillion 1 petasecond = 31.7 million years Quintillion 0.43 Es ≈ the approximate age of the 10 18 exa E 1,000,000,000,000,000,000 Universe Sextillion Volume of seawater in the Earth's 10 21 zetta Z 1,000,000,000,000,000,000,000 oceans is ≈ 1.369 zettalitres Septillion The observable universe is 10 24 yotta Y 1,000,000,000,000,000,000,000,000 estimated to be 880 Ym in diameter. ICRAR � 5
Scientific Method Hypothesis Theory Testable Yes Yes Falsifable Yes Yes Well No Yes substaintiated Well tested No Yes ICRAR � 6
What is Astronomy Literally: aster = star + nomie = naming Astronomy is the observational scientific study of the universe and its contents. Astrophysics is the combination of astronomy with theoretical understanding of the processes taking place in astronomical objects. ICRAR � 7
How fast are we moving The Earth is rotating at 0.46 km/s The Earth moves around the Sun at 30 km/s Our Solar System is moving around the Milky Way at 300 km/s Our Galaxy is respect to other galaxies 540 km/s ICRAR � 8
Spot Quiz For the full SKA ICRAR � 10
SKA on one slide • 10 Work-packages: • Two phases: • Assembly • SKA1 and SKA2 • Integration and Verification (AIV) • Two telescopes: • Central Signal Processor (CSP) • SKA1-low (~130,000 dipoles) • Dish (DSH) • SKA1-mid (196 15m dishes) • Infrastructure Australia and Africa • Three host countries: (INFRA AU/ INFRA SA) • Australia (Murchison shire) • Low-frequency Aperture Array (LFAA) • Mid-frequency Aperture Array (MFAA) • South Africa (Karoo) • Signal and Data Transport (SaDT) • United Kingdom (HQ) • Science Data Processor (SDP) • 12 member countries: • Telescope Manager (TM) • Australia , Canada, China, France, • Wideband Single Pixel Feeds (WBSPF) India, Italy, New Zealand, South Africa , Spain, Sweden, The • Cost cap at € 650M for SKA1 Netherlands, United Kingdom • Power cap ~5 MW ICRAR � 11
Some of our requirements for Phase 1 • SDP_REQ-289 Maximum science product preservation lifetime. The SDP shall preserve science data products for not less than 50 years from the start of science operations. • SDP_REQ-705 preserved Science Data Product growth rate The SDP shall support a growth rate of preserved science data products per year of 34 PB for MID and 11 PB for LOW covering at least the science data products of the High Priority Science Objectives • SDP_REQ-669 Buffer size The SDP shall be able to store a minimum of 12 hours (TBC-010) of visibility data (at the maximum data rate) in its buffer (where it is either awaiting processing or being processed) and to jointly image at least 6 hours of visibility data. ICRAR � 12
FAST ICRAR � 14
Redshift ICRAR � 15
Wow! Signal - 1977 Credit: Big Ear Radio Observatory and North American AstroPhysical Observatory (NAAPO) ICRAR � 16
Spot Quiz For the full SKA ICRAR � 17
How faint are the signals? Energy of a pair of falling feathers < 60 microjoules Energy collected by ALL radio telescopes, prior to 2014, less than a pair of falling feathers ICRAR � 20
Electromagnetic Spectrum N 2 , O 2 , O 3 Radio H 2 O, CO 2 , O 2 ICRAR � 21
Radio and Optical M82 M81 NGC3077 � 22 ICRAR
What Radio Astronomy can see.... HI - Neutral Hydrogen But we can also see over 150 molecules 500+ lines have been identified, but not classified These include: - Water (H 2 0) - Methanol (CH 3 OH) wood alcohol - Hydrogen Sulphide (H 2 S) - Amino acetonitrile - Ethyl methyl ether (C 2 H 5 OCH 3 ) (NH 2 CH 2 CN) - Ammonia (NH 3 ) a simple organic compound - Carbon Monoxide (CO) - Glycoaldehyde - Acetylene (C 2 H 4 ) (HOCH 2 CH 2 OH) - Formaldehyde (H 2 CO) a simple sugar embalming fluid ICRAR � 23
Radio Telescopes need a large collecting area Radio Photons are Wimps • X-Ray photons => 10ev - 100KeV • Optical photons of 600 nanometre => 2 eV • Radio photons of 1 metre => 0.000,001 eV ICRAR � 24
Second Reasons A larger aperture has better resolution ∆θ ≈ 1.22 λ ∆θ D ∆θ = 1” λ D D Optical 500nm 125mm D Radio 21cm 53.37km � � � ICRAR � 25 � � �
SKA Images ICRAR � 26
Direct and Indirect Imaging • Direct Imaging - The image is projected onto a detector. - Examples: your eye, cameras, optical telescopes, single-dish radio telescopes • Indirect Imaging - Used where we cannot form a direct image of the object on the focal plane - We infer the properties of the object from certain characteristics of the received electromagnetic field - Examples: interferometry, NMR, ultrasound, PET "PET -MIPS-anim" by Jens Maus (http://jens-maus.de/) ICRAR � 27
How we build images Credit: Tom Oosterloo, ASTRON ICRAR � 28
Event Horizon Telescope ICRAR � 29
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What happens to the data MWA MWA 1.4TB/h 5 PB/y Data Intensity ASKAP ASKAP Astronomy 9TB/h 5.5 PB/y Antennas / Science Data Correlator Archive SKA1-Low SKA1-Low Digitisers Processor 1,800TB/h 150 PB/y ICRAR � 31
Spot Quiz For the full SKA ICRAR � 32
Size Comparison ICRAR � 35
Biggest (so far) ICRAR � 36
Little Pluto ICRAR � 37
Reality is “weirder” than fiction ICRAR � 39
Space is B IG The nearest planet Proxima Centauri b is 4.24 light years away or 4.24 x 9,460,730,472,580.8 km or 40,113,497,203,742.59 km Max Speed 39,897 61,436 690,000 (km/H) Time (Years) 114,696.14 74,483.94 6,631.93 ICRAR � 40
Saying hello to Proxima Centauri b ICRAR � 41
Gravitational Waves ICRAR � 42
Neutron Star Diameter: 10-30km Mass: 2x Sun (Theory says 3x is the max) Spin: 716Hz -> Once every 8.5s So dense that a single teaspoon would weigh a billion tons ICRAR � 43
What is a Gravitational Wave Gravity • Einstein’s General theory of relativity says: gravity is a manifestation of the curvature of 4- dimensional (3 space + 1 time) space-time produced by matter • If the curvature is weak, it produces the familiar Newtonian gravity • When the curvature varies rapidly due to motion of the object(s), curvature ripples are produced. These ripples of the space-time are Gravitational-waves. • Gravitational-waves propagate at the speed of light. ICRAR 2019 ICRAR � 44
Strain Strain [(Change of length)/(Length)] : h ~ 10 -21 Sensing changes over 4 km to a thousandth the size of a proton ICRAR 2019 ICRAR � 45
What it looks like ICRAR 2019 ICRAR � 46
Current approach • Traditional Signal Processing • Noise Whitening • Matched Filters ICRAR 2019 ICRAR � 47
Whitening Take the Fourier transform • Divide by the Amplitude Spectral Density • Convert back to the time domain • ICRAR 2019 ICRAR � 48
tp-3-[37552 1]: m1: 6.18, m2: 48.01, dist: 1468.13, inc: 1.66 snr: 3.85, cm: 13.69 snr bin: [0. 1. 0. 0. 0. 0. 0.], out: [0.34 0.69 0.24 0. 0. 0. 0. ] chirp mass: [0. 1. 1. 0. 0. 0. 0. 0.], out: [0.47 0.51 0.37 0.03 0. 0. 0. 0. ] ICRAR 2019 ICRAR � 49
Spot Quiz For the full SKA ICRAR � 50
Trappist-1 ICRAR � 51
Where did we get the term ‘Big Bang’ Sir Fred Hoyle first coined the phrase 'Big Bang' he did so in order to mock the theory. Hoyle was a firm believer in the alternative steady state theory which gives the universe no start or end. Basically Sir Fred was taking the piss out a theory he thought was bl**dy stupid ICRAR � 52
What was before the big bang? Nothing or Something It’s a bit like asking what is North of the North Pole ICRAR � 53
How did it start? We don’t know ICRAR � 54
Galilean relativity ICRAR � 55
Einstein's relativity postulates It required the genius and the courage of Einstein to accept the third alternative. His special relativity is based on two postulates: All laws of nature are the same in all inertial frames This is really Galileo relativity The speed of light is independent of the motion of its source This simple statement requires a truly radical re-thinking about the nature of Albert Einstein 1879-1955 space and time! ICRAR � 56
Pythagoras ICRAR � 57
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