Exploring the Universe Through the Hubble Space Telescope

Transcription

1 Exploring the Universe Through the Hubble Space Telescope WEEK FIVE: THE HUBBLE DEEP FIELD + LIMITATIONS OF HUBBLE, COLLABORATIONS, AND THE FUTURE OF ASTRONOMY Date: October 14, 2013 Instructor: Robert Arn Robert@astroarn.com Website: AstroArn.com

2 Most of the Universe is not visible to the naked eye Best conditions 3 million years Ground based telescopes and cameras can see 10 billion light years Hubble can detect beyond that and can get optical structure

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5 Hubble Ultra Deep Field 60x less than the size of the full moon Contains 4x the number of galaxies than the number of stars counted with the naked eye Galaxies from 1 to 13 billions light years The most distant look (optical) at our universe

6 Cosmology the area of astronomy dedicated to the study of the origin, evolution, and fate of the universe as a whole Prior to 1960 there were two competing theories Steady State the universe had no beginning, no end, and there was a constant galaxy density. As galaxies got further away, new galaxies formed. Big Bang the (current) universe had a beginning and the galaxy density decreases in the expanding universe. Galaxies should evolve over time.

7 Strong Protons and Neutrons are made up of quarks Strong force binds quarks together Current theory is quantum chromodyanmics 10E39x stronger than gravity Range: 10E-15m through Gluons Weak Many different particles Drives Radioactive Decay (Sunlight) 10E25x stronger than gravity Range: 10E-17m Electromagnetism Responsible for almost all phenomena in daily life (except gravity) Holds atoms together 10E36 stronger than gravity Range: Inf through Photons Gravity Incredibly weak force Only operates between two object which must have mass Currently describe by general relativity Range: Inf through???

8 An Early History of the Universe Starting with a singularity Infinite density, no volume, no time Timeline can be broken into major eras: Radiation Era Matter Era Starting with the formation of atoms at 2x10E12 seconds (~5000 years)

9 Epoch Beginning Time Density (kg/m^3_ Temperature Description Planck 0s Inf Inf Unknown Physics GUT 10E-41s 10E95 10E32K Strong, weak, and EM Forces Unified Quark 10E-35s 10R75 10E27 Weak and EM Forces Unified Lepton 10E-4s 10E16 10E12 Forces are not unified Nuclear 10E2s 10E4 10E9 Deuterium and Helium Formed Atomic 5x10E4 YR 6x10E-16 16,000 Matter begins to dominate; atoms form Galactic 10E8 YR 10E First stars and quasars shine Stellar 3x10E9 YR 2x10E Galaxies merge and grow; star still form

10 10E25 meters = 1,057,023,410 light years After Inflation the Universe continued to expand at a much slower rate However, the universe is expanding faster now than is was from the Quark epoch (this is attributed to dark energy)

11 In 1960, Arno Penzias and Robert Woodrow Wilson at Bell labs created a new radio antennae to test satellite communications Mystery interference Months of cleaning and testing Princeton Nobel Prize in 1978 to Penzias and Wilson CMB Strong evidence for Big Bang Model

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13 Cosmic Microwave Background Radiation Located at redshift 1100 corresponding to a universal age of 400,000 years old. Original map reveled the existence of the CMB, however more sensitive instruments were needed for implications in formations Variations first detected by COBE (Cosmic Background Explorer) Recently (past decade) a dedicated space telescope took the most detailed map of CMB (MAP Microwave Anisotropy Probe) Differences in colors are within 1/400,000,000 th of a Kelvin degree

14 It is impossible to see past the CMB With detailed CMB maps we have a set of initial conditions with what the universe looked like 380,000 years With the Hubble Ultra Deep Field we can look back to ~700,000 years The structure of what we see with Hubble has been used in conjunction with the CMB maps to try to figure out how the first galaxies and stars formed More advanced telescopes are needed to see the universe from 380,000 years to 700,000 years (due to extreme redshifting)

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16 History of the Hubble Deep Field Story of creation of image Bob Williams Director of the Space Telescope and Science Institute This image taken in 1996 Contains 3000 galaxies 0.7% the size of the full moon near the Big Dipper 175 research papers off this single image

17 Hubble Ultra Deep Field In 2004 the upgraded ACS camera took another long image 268 hour exposure Combination of 808 individual frames Took 400 Hubble orbits to collect data Amounts to 10% of yearly time with Hubble Able to see objects 4 billion times fainter than naked eye Contains 10,000 galaxies 1.7% of the area of the full moon If the galaxy density was spread over the entire sky it would reveal a population of 130 billion galaxies in the observable universe.

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20 Major Areas of Future Research Cosmology being able to see the first stars and first galaxies can help us understand the fate of the universe give us better clues as to what dark matter and dark energy could be and allow us to understand stellar formation and galaxy formation First stars and galaxies are redshifted so much they are in the infared - not optical wavelenghts Exoplanets detection of Earth sized planets and atmospheres on planets lead to the possible detection of complex life elsewhere in the universe

21 The Exoplanet Problem Stars are bright planets are not Consider trying to find Earth from Alpha Centuri (4.4 ly away) Earth is 20 billion times fainter Located ¾ of an arc second away from sun Consider trying to find Jupiter from Alpha Centuri Jupiter is 300 million fainter and 3 arc seconds away from sun As the distance between the sun and other stars increases, the separation distance gets smaller

22 Sirius white dwarf companion is 10,000x fainter and 7 arc seconds Near the limit of Hubble capabilities Hubble is not capable of imaging a Earth or Jupiter around any star

23 Exoplanet Detection The first Exoplanet was discovered in 1992 Most Exoplanets discovered through indirect methods only Method One: Use a spectrograph to find redshift/blueshift of a star If there is another large mass in the solar system, the star and the other mass will orbit each other The velocity change we can detect is equivalent to a brisk walk (3-4mph) Only massive planets are detected this way much larger than Jupiter 80% of planets found so far are larger than Jupiter No Earth sized planets have been discovered

24 So far only 15% of star systems have shown to have Exoplanets The true percentage is probably closer to 50% Method Two: Study stars looking for changing of brightest as a planet moves in front of the parent star Jupiter passing in front of the sun would dim the output by 1% Earth passing in front of the sun would dim the output by 0.01% 40 Jupiter sized planets have been detected from the ground using this method Need to have a dedicated telescope searching for exoplanets

25 In 2009 the Kepler Space Telescope was launched It s goal is to continuous monitor 100,000 stars in Cygnus for 4 years Has the capability of detecting Earth sized planets Kepler Space Telescope launch story

26 As of October 12, 2013 Potentially Habitable Exoplanets Potentially Habitable NASA Kepler Candidates Subterran (Mars-size) 0 Terran (Earth-size) 0 [Main Goal] Superterran (Super-Earth) Confirmed Exoplanets NASA Kepler Candidates Other Unconfirmed Exoplanets 998 3, Bad news: Confirmed as of July 2013, Kepler is not able to function on it s original mission

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28 Earth-like Planet = Planet with 0.5 to 1.4 Earth radii planet orbiting in the habitable zone Nu_Earth = Stellar frequency of Earth-like planets Delta_Earth = mean distance between earth-like planets P10_Earth= probability of an Earth like planet being within 10 light years of Earth

29 In 2004/2006 Hubble directly imaged an Exoplanet Planet is 20x further from Fomalhaut than Jupiter is from Sol Planet is 3x the mass of Jupiter Has a period of 870 years

30 James Webb Telescope Supposed to be the successor to the Hubble Space Telescope Has a 6.5 meter segmented mirror that will unfold once in orbit Telescope and instruments optimized for infrared Better for Exoplanet detection (since the difference in brightness between stars and planets are smaller) Capable of seeing further back in time (infrared red shifting)

31 Huge sun shield to block light from the sun, moon and earth (great sources of infrared light) Will be in Lagrange Point around Earth 1.5 million km away Will launch in 2012 I mean 2014 I mean 2015 Well maybe in 2018 Predicted to be able to directly image Jupiter-sized planets

32 Terrestrial Planet Finder Interferometer Will launch as early as 2020 Set of 3m mirrors flying in perfect alignment over 100m Mirrors act as baseline size 100 meter effective mirror in space Predicted to be able to directly image Earth-sized planets around nearby (100 light years) stars Will be able to take spectrum collect detailed information on atmosphere could indicate presence of life

33 Fate of Hubble Space Telescope No more repair missions can be made (no shuttle craft to get up there) Hopefully, it will continue to function for another 10 years If nothing is done, the orbit will decay and most of it will burn up in Earth s atmosphere Some pieces will impact the ground intact SM5 attached port for robotic probe to change orbit