Transcript Three Years of SETI@home A Status Report

SETI on the SKA
Dan Werthimer
University of California, Berkeley
http://seti.berkeley.edu/
• SETI history
• SETI today
• SETI future (SKA)
• Signal processing
NOT FUNDED
NOT FUNDED
NOT FUNDED
Porno in space:
FUNDED!
First Radio SETI
• Nikola Tesla (1899)
– Announces “coherent signals from Mars”
• Guglielmo Marconi (1920)
– Strange signals from ET
• Frank Drake (1960)
– Project Ozma
– one channel, 1420-1420.4 MHz
Traditional SETI dogma:
ultra narrow band sine waves
barycentric, beacons, FGK stars
21 cm
Future dogma:
many bandwidths, frequencies,
drifting signals, pulses,
M stars, galaxies
It’s naïve to think we know how
best to search today, given our
history of changing SETI fashion.
• Multiple strategy is best
(IR, Vis, Radio, pulse, continuous, targetted
sky survey…)
• Half of astronomy discoveries are serendipitous
• Examine glitches in data
• Data Mining Experiments
OPTICAL SETI
1961 Charlie Townes Paper
largely ingored until 1999
1971 Cyclops report calculates radio >> optical
Today’s lasers can communicate across galaxy
Optical SETI experiments
• Lick Observatory
(Lick, Seti Institute, Berkeley)
• Harvard (targetted  sky survey)
• Princeton
• Berkeley
10-meter Keck
Telescope
Survey: 650 F8 – M5 V, IV
Hipparcos
V < 8.5
B-V > 0.55 (F8V)
Sep > 2 arcsec
Age > 2 Gyr
Keck Optical SETI – Data Mining
• Geoff Marcy, Amy
Reines
• 650 stars (planet data)
• Echelle Spectrometer
• Can detect 10KW
narrow band signal
(10 KW laser on 10
meter telescope)
SETI GOAL:
SkyCoverage * FreqCoverage * Sensitivity^-3/2 * Nsignaltypes
solid angle vs number of nearby FGK stars?
FreqCoverage vs Noctaves?
Pulses vs sinewaves vs drifting vs broadband…?
FreqCoverage, SkyCoverage, signal types: other telescopes
sensitivity: SKA
Radio SETI
Targetted Search Strategy
Project Phoenix - Seti Institute
Sky Survey Strategy
Serendip, SETI@home - UC Berkeley
Southern Serendip
- Australia
Meta II
- Argentina
Seti Italia
- Bologna
SETI Programs at the
University of California
NAME
TIME SCALE
SEARCH TYPE
SERENDIP
1 second
Radio sky survey
SETI@home
ms to second Radio sky survey
ASTROPULSE us to ms
Radio sky survey
SEVENDIP
ns
Visible targetted
SPOCK
1000 seconds Visible targetted
Dyson Search Years
IR excess
University of California, Berkeley SETI Program
• Graduate Students
Chen Chang, Karl Chen, Paul Demorest, Nia Imara, P. Monat, A. Parsons
• Undergraduate Students
Noaa Avital, Brian Boshes, Henry Chen, Charlie Conroy, Chris Day, Daniel
Hsu, Wonsop Sim, Ryo Takahashi
• Astronomers and Computer Scientists
David Anderson, Bob Bankay, Jeff Cobb, Court Cannick, Eric Korpela,
Matt Lebofsky, Jeff Mock, Dan Werthimer, Rom Walton
• Administrative Staff - None
SERENDIP IV
Photos Courtesy NAIC Arecibo Observatory, a facility of the NSF
•
168M channels
•
•
100 MHz Band centered on 1420 MHz •
Carriage House 1 line feed
Operating since 1997
Why SETI@home?
• Coherent Doppler drift correction
– Narrower Channel Width->Higher Sensitivity
• Variable bandwidth/time resolution
• Search for multiple signal types
– Gaussian beam fitting
– Search for repeating pulses
Problem: Requires TFLOP/s processing power.
Solution: Distributed Computing
The SETI@home Client
SETI@home Statistics
TOTAL
RATE
5,064,550 participants
(in 226 countries)
2,000 per day
2 million years
computer time
1,200 years per day
4*1021 floating point
operations
65 Tera-flops
SETI@home in Canada
• 255,426 participants (0.8% of population)
• 112,000 years of computer time
• 72 million work units
Web site: 2 million hits/day
200,000 visitors/day
(stats & games popular; science less popular)
100,000 children, families
(including congress members and their kids)
> 7,000 schools
Desired SKA Parameters
• Wide bandwidth
• 1 M beams
• fat beams
• short dwell times (~ 100 seconds)
Gaussian Candidates
BOINC
• Berkeley Open Infrastructure
for Network Computing
– General-purpose distributed
computing framework.
– Open source.
– Will make distributed computing
accessible to those who need it.
(Starting from scratch is hard!)
BOINC Projects
• SETI@home
(Berkeley))
• Astropulse
(Berkeley)
• ClimateModeling@home (Oxford)
• Einstein@home
(Caltech)
• Folding@home
(Stanford)
• ParticlePhysics@home
(CERN)
• Stardust@home
(U. Wa, Berkeley)
AstroPulse
• Sky survey
– Covers decs 0 to 30
– ~3 years of data recorded so far.
• Good time resolution
– Sensitive to 0.4 µs radio pulses at 21 cm
• DM range
– -1000 to +1000 pc/cm3
• Sensitivity
– 10-18 W/m2 peak (Coherent de-dispersion)
Piggyback ALFA Sky Survey
• Improved sensitivity
– Tsys, integration time
• Uniform sky sampling
– galactic plane concentration
• Multibeam RFI rejection
• Larger Bandwidth
Search for Optical/Radio Signals from Dyson Sphere Candidates|
Charlie Conroy
• Looked for IR excess from >500
stars
• All stars had age > 1 Gigayear
• 33 stars found with 12m excess
• Searched for anomalous radio
detection using SETI@home and
SERENDIP IV databases
• Searched for optical pulse
emission using OSETI experiment
• Thus far, none of the 33 sources
have shown anomalous optical or
radio emission
Color excess using 2MASS K band data and 12, 25, 60, & 100
micron IRAS data. An excess at K-[12] is clearly visible and
disappears by K-[25]. Dotted lines are Gaussian fits to the
distributions. The 33 IR excess candidates have K-[12] > 3 above
the mean.
‘Prelude’ Precedes SonATA
In Fall 2004
For Use On The ATA-32
3 beams with 30 MHz each – PCs with accelerator cards
Future SETI Spectrometers
2015
4 THz
2020
128 THz
400 beams
10 GHz each
12,800 beams
2025
4000 THz
40,000 beams
2030
128,000 THz 1M beams
Moore’s Law in FPGA world
Computational Density Comparison
Processor Peak
1000000
FPGA 32-bit int MAC
100X More efficient
than micro-processors!
100000
10000
FPGA maximum sustained performance
1000
10/28/19 3/11/199 7/24/199 12/6/199 4/19/200 9/1/2002 1/14/200
95
7
8
9
1
4
100000
Release Date
3X improvement
per year!
10000
MOPS (32 bit MAC)
(MOPS/MHz)*lamda^2
10000000
1000
100
10
1
12/1/19 6/19/19 1/5/199 7/24/19 2/9/199 8/28/19 3/15/20 10/1/20 4/19/20 11/5/20 5/24/20
96
97
8
98
9
99
00
00
01
01
02
Release date
Multi-Purpose FPGA-Based
Spectrometer (NSF, A. Parsons)
200 Aux. I/O
I
200 Mhz
ADC
Q
200 Mhz
ADC
{
Pol. 1
Arecibo
Feed
Array
I
Pol. 2
Xilinx
Virtex-II 6000
FPGA
200 Mhz
ADC
{
Q
Xilinx
Virtex-II
1000
FPGA
Compact PCI
Backplane
200 Mhz
ADC
256 MB DRAM
Software
SETI Applications
• ALFA Sky Survey (300 MHz x 7 beams)
• Parkes Southern SERENDIP
• JPL/UCB/SI Survey (20 GHz Bandwidth)
• SETI Italia (Bologna)
• SETI@home
Astronomy Applications
• GALFA Spectrometer – Arecibo Multibeam Hydrogen Survey
• Astronomy Signal Processor – ASP – Don Backer (pulsars)
• ATA4 Correlator F Engine
• Reionization Experiments (Backer (UCB), Chippendale/Ekers (ATNF))
Filter Response:
PFB vs. FFT
Next Generation Board
BEE2 (2004/5) – Chen Chang
• 5 Xilinx XC2VP70
• 40 GB RAM (8 GB each chip, 13Gbit/sec/chip)
• 18 10Gbit/sec infiniband ports
• 50 boards per rack, Tbit/sec infiniband switch
• Applications:
– 1 GHz, 1 Gchannel spectrometer (single board)
– Next Generation ATA backends (ata32 = 2 boards)
– SKA imaging
B2 Module: board layout
• 5 compute
elements on a
board
• Up to 400 billion
CMAC/s
performance
• communication
bandwidth:
– 240 Gbps onboard 360 Gbps
off-board
Global Interconnects
Ethernet Switch
• Commercial Infiniband switch
from Mellanox, Voltaire, etc.
– Packet switched, nonblocking
– 24 ~ 144 ports (4X) per
chassis
– Up to 10,000 ports in a
system
– 200~1000 ns switch latency
– 400~1200 ns FPGA to FPGA
latency
– 480Gbps ~ 2.88Tbps full
duplex constant cross section
bandwidth
– <$400 per port
Compute
Node
#1
Compute
Node
#N
Infiniband Crossbar Switch
19” 48RU Rack Cabin Capacity
• 40 compute nodes in 5 chassis (8U) per rack
• Up to 16 trillion CMac/s performance per rack
• 250 Watt AC/DC power supply to each blade
• 12.5 Kwatt total power consumption
• Hardware cost: ~ $1M
Unified Digital Processing Architecture
Channel
Reorder
Buffer
imaging
Infiniband
Swtich
An #N
Polyphase
Filter
Banks
XMAC
Beamforming
Channel
Reorder
Buffer
Infiniband Swtich
An #1
Polyphase
Filter
Banks
Spectrometer
Pulsar
Searching
• Distributed per antenna spectral channel processing
• Multiple reconfigurable backend application processing
• Commercial packet switched interconnect
Why you might not
want SETI experiments
on the SKA:
Desired SETI SKA Parameters
• Wide bandwidth (0.1 to 35 GHz)
• 1 M beams
• Wide beams (primary and synthesized)
- compact array strongly preferred!!!
(for both targetted and sky survey)
Seti Haiku
Searching for life
Answers are revealed
About ourselves
Paula Cook, Duke University
One million earthlings
Bounded by optimism
Leave their PC’s on
Dan Seidner
Seti.org
Planetary.org
Seti.berkeley.edu