Day two of the New Frontiers wrap-up conference. This is a slow liveblog with more cosmology and life in the universe. Yesterday’s summary is here
This is a slow liveblog – part II will be tomorrow with more cosmology and life in the universe
Seed funding was provided to 20 investigators and small groups to start exploratory research, and, now, it is time to say what they found.
This follows up from the New Frontiers kick-off conference back in 2012.
We start the morning with some more cosmology before going to alien life after lunch.
- Measuring the Multiverse: Raphael Bousso (UCB)
Continuing from where Aguirre left off, with some background intro on the cosmological constant leading to eternal inflation and the string landscape.
Most bubble vacua have large cosmological constants, small horizons, few internal quantum states and no observers – anthropic bias.
Qualitative difference to get an interesting enough universe for there to have been a phase transition with reheating.
Old school “one dimensional” multi-vacua multiverse falsified (I think this is a very theorist use of the word “falsified”, but fair enough).
Time emergent from entropy increase
long term single vacuum de Sitter with T ~ √ Λ
– digression to Boltzman brain problem
multi-vacua avoids this if vacuum decays faster than it spawns brains.
- Testing the Multiverse with Cosmic Bubble Collisions: Matthew Kleban (NYU)
Very good overview of phase transitions and bubble production.
Is the multiverse testable? Well, yes, duh…
- positive curvature – multiverse predicts negative curvature
- low power in scalar fluctuation at low multipoles
- bubble collision signatures
looked at alternative picture for bubble formation – repeated bubble collisions in extra dimensions to drive slow roll inflation – hmmm
Stringy, toy model does fun stuff with quantitative predictions in interesting range.
Guido D’Amico, Roberto Gobbetti, Matthew Kleban, Marjorie Schillo
Journal of Cosmology and Astroparticle Physics, Issue 11, article id. 013, pp. (2013) (arXiv)
- CMB Polarization, 21cm cosmology and testing the multiverse: Chao-Lin Kuo (Stanford)
Nice intro on polarization and scattering
Quick summary of BICEP2 3 year result, decomposing into E and B modes, claim 5+ σ detection of B modes.
Big question is whether it is coming from CMB or foreground, of course.
Definite lack of power at low multipoles, especially around l ~ 20-30
Is this a sign of inflation? (see Bousso et al. arXiv:1404:2778)
Is polarization due to dust foreground? TBD
Planck data release + Keck Array + BICEP3 will determine in near future.
So, the CMB people are not talking enough to the galactic dust people, because my impress is that a lot more was known about foreground dust than they think, even if there were not global maps of high precision polarization fraction.
Low intensity dust emission tends to have high polarization fraction…
Interesting overview of future prospects.
- Search for drifting constants via extra-galactic alcohol: Wim Ubachs
Are constants constant?
Test by looking at observables at different times in universe.
Was Leibniz or Voltaire right?
Looking at ratio of electron mass to proton mass. Existing limits are changes by less than 10 parts per million over last 10 billion years, based on UV spectra.
Looking at methanol to get better sensitivity.
Julija Bagdonaite (1), Mario Daprà (1), Paul Jansen (1), Hendrick L. Bethlem (1), Wim Ubachs (1), Sébastien Muller (2), Christian Henkel (3,4), Karl M. Menten (3) ((1) VU University Amsterdam, Netherlands (2) Onsala Space Observatory, Sweden (3) Max-Planck-Institut für Radioastonomie, Germany (4) King Abdulaziz University, Saudi Arabia) Physical Review Letters, vol. 111, Issue 23, id. 231101 (arXiv)
Constraint improved by 2 orders of magnitude.
Also looked ad GD-133 using COS to look at Ly absorption to look for equivalence principle violations, dependence on gravitational potential dependence.
Also looking at GD29-38
Got limits on equivalence principle violation at 50 ppm level. Not bad.
- Global structure of the multiverse and the measure problem: Alexander Vilenkin (Tuft)
Sorry, missed this one.
Lots of discussion on whether we can define “beginning”…
and we are back:
- The search for life in extremely exotic environments A strict test for life’s cosmic ubiquity: Jonathan Lunine (Cornell)
Looking at Titan, natch.
Interesting discussion on H-bonding at low temps in ethane/methane solvent.
Cyanogenic polymers.Molecular dynamics/mechanics sims to look into assembly – made “azotosomes” – spherical self assemblies, not known if stable, yet.
Also self-assembling monolayers and helical polymers. Polyacetylene for light harvesting?
Look potentially interesting.
Cassini saw large transient features in the seas on Titan – could be something interesting “growing” – comes out next week.
- Discovery of Earth-like Planets and Signals from Intelligent Life: Geoffrey Marcy (UCB)
Looking for coherent optical emission with the Keck Telescope, and looking for Dyson spheres in Kepler photometry.
Begins with overview for cosmologists of state of exoplanet discovery.
State of exoplanet discovery is awesome.
There are lots of exoplanets, especially nice little ones.
Can see 100W lasers to 10 pc or so – have couple of interesting looking candidates with ~8 σ emission – should be looked at further.
- Stellar Lighthouses: Decoding Signatures of Advanced Civilizations in Precision Stellar Photometry: Lucianne Walkowicz (Princeton)
Overview of Kepler photometry and modern ultrahighprecision stellar photometry.
Can do stuff other than just find planets with time series photometry like that.
Pick up stellar variability; flares, stellar spots, pulsations, as well as transits.
Also can do very good asteroseismology.
Very large data sets, look for unknown kinds of signals using machine learning – specifically unsupervised learning.
Clustering and looking for outliers
Finding new heartbeat stars and some interesting new variables, including very rapid rotators with strong flares.
Couple of WTF variables – one which turned out to be a diffraction spike rotating with spacecraft reorientation…
a couple of the others do look very interesting, but they also look stellar, not naively artificial
- Constraining the Abundance of Kardashev Type II and III Civilizations From Large Area Infrared Surveys: Jason Wright (PSU)
Background on Kardashev scale and concept of categorizing civilizations by energy use (not intended to be a normative description – just a prescription).
Discussion of time scale to convert from KII to KIII – argument for why once you can spread to adjacent stars spread across galaxy is rapid compared to galaxy lifetime.
Ought to look both for galaxy spanning civilizations in other galaxies and KII civilizations in the Milky Way – low effort search worth while at this stage as secondary to other surveys.
So we did.
Discussion of artifact transit and KIC12557548 – per request from Marcy and Walkowicz – it is a mystery
WISE catalog – filtered high galactic latitude extended red sources
have a 30,000+ interesting candidate very red sources –
looked at the 4,000 best sources to classify them
Split them into already know sources; garbage and ghosts; and new very red sources that could use a closer look.
Students start this week at SETI institute to do followups.
Out of 105 resolved WISE sources in local universe less than 1,000 are consistent with having significant KIII coverage, and most of those are known starburst or merger galaxies – so we can put strong constraints on fractional abundance of KIII or even partial KIIIs in local universe.
Can push limits down a lot further with modest effort, dust modeling, look at few thousand more candidates, chase down still unknown sources.
Next step is cross-correlate with GAIA catalog – particularly good for filtering KII sources in crowded low galactic latitude regions.
On thing mentioned by several speakers is that we are not far enough a long for a lot of the projects – the projects are all nominally 2 years, and funding commenced about 21 months ago, but that effectively meant that most started serious efforts about 18 months ago, and so many only have preliminary results or “in prep” results.
There’s a reason a lot of astro/physics projects operate on three year cycles.