Twitter Facebook LinkedIn YouTube

    Prof. Lubin from UC Santa Barbara delivered two seminars at Strathclyde University on Tuesday 24th of June 2014. The first entitled “Searching for the Beginning of the Universe”. Prof. Lubin discussed our understanding of Cosmic Microwave Background and Gravitational Waves and the difficulties faced in attempting to accurately search for and measure these. In the second seminar entitled “Prospects for Directed Energy Planetary Defence” Prof. Lubin presented the DE-STAR (Directed Energy Solar Targeting of Asteroids and exploration) project and its potential not only for tackling asteroids and comets, but also for relativistic spacecraft propulsion and interstellar and intergalactic communication.

    Here are the abstracts:

     

    Searching for the Beginning of the Universe

    Philip Lubin

    Physics Department, University of California, Santa Barbara, CA 93106-9530, 805-893-8432, lubin@deepspace.ucsb.edu

    Abstract: Our ideas and understanding of the earliest moments of the universe are largely based on both our observation of and the lack of observation of phenomenon. This combined with our lack of a fully quantized theory of gravity have led us to postulate ideas that are often difficult to test, let alone understanding why they occur. For example, we do not observe magnetic monopoles but we do observe a relative isotropy. These and other ideas have brought us to postulate a hyper expansion phase we call inflation to bring our observations into concordance. But how do we observe direct consequences of this phase if it existed? One consequence of many inflationary models is that gravitational waves will be generated during this time in excess of what we would normally expect if this phase did not happen. These gravitational wave are beyond our current abilities to directly detect but we may be able to detect them indirectly via there coupling to the photons that arise later, the so called Cosmic Microwave Background (CMB). Due to the topological nature of gravitational waves we expect a particular pattern of this effect on the linear polarization state of the CMB in the form of vorticy like terms (a Curl like component) analogous to the structure of magnetic fields and hence the term B modes. Unfortunately, the many of models of inflation lack predictive power as to the magnitude of the gravitational waves generated and hence we are left to search for phenomenon which may or may not be detectable with current or foreseeable technology. Searches are underway to try to observe or limit this effect. Recent observations have claimed detection of B modes in the CMB at a level that is puzzling. In this talk I will review the overall issues related to searching for inflation and the status of the CMB sky as measured by the ESA/ NASA Planck mission and discuss the highly complex nature of the many foregrounds that must be understood to properly search for inflationary signatures, including B modes.

    Prospects for Directed Energy Planetary Defense

    Philip Lubin

    Physics Department, University of California, Santa Barbara, CA 93106-9530, 805-893-8432, lubin@deepspace.ucsb.edu

    Abstract:  Our planet is bombarded daily by about 100 metric tons/ day of asteroid and meteoritic debris which normally burns up harmlessly in the upper atmosphere. Occasionally we are hit by an object large enough to penetrate to low enough altitudes to do significant harm as we saw last year in Russia. Historically such events have played a large role in the evolution and extinction of a number of species. It is inevitable that large scale destruction will occur again if nothing is done to mitigate it. The consequences of doing nothing are extremely dangerous over long periods of time. Yet even over the span of a human lifetime an event with energy deposition comparable to that of strategic nuclear weapons is not atypical.  I will discuss the threat as well as possibilities for using directed energy as a possible means of both a medium and long term mitigation strategy. The same type of system is capable of a number of other uses, beyond including planetary defense, such as space debris removal, photon driven propulsion allowing relativistic probes and interstellar and intergalactic communications and beacons as well as SETI searches for comparably advanced civilizations.. Recent developments in photonics allow such a system whereas even a decade ago it would have been simply science fiction. While a very difficult engineering challenge no technical miracles need be invoked (except for funding).  The generic system is called  DE-STAR for Directed Energy Solar Targeting of Asteroids and exploRation.  DE-STAR comes in two basic forms, a large standoff system we just refer to as DE-STAR and a small standon system for probes sent to a dedicated target we call DE-STARLITE.  DE-STAR is an  orbital modular phased array of lasers, powered by the sun.  Modular design allows for incremental development, test and initial deployment, lowering cost, minimizing risk and allowing for technological co-development, leading eventually to an orbiting structure that could be erected in stages.  Ground based variants are also be possible but atmospheric perturbations severely limit this with currently known adaptive optics techniques. The main objective of DE-STAR would be to use the focused directed energy to raise the surface spot temperature of an asteroid to ~3000K, allowing direct evaporation of all known substances. Targets with volatiles, such as comets, require much lower effective temperatures and hence fluxes. The system is completely scalable and being modular allows for systems from small size (sub meter class) that could be used on a dedicated mission spacecraft that would rendezvous with a threat to a large system that is a completely standoff unit capable of deflecting all known threats with mitigation starting beyond 1 AU. I will discuss both approaches. The system is inherently multi tasking allowing for simultaneous multiple target engagement and multiple use if needed. A large baseline system, suitable for full planetary defense is also capable of propelling a 10,102, 103, 104 kg spacecraft to 1 AU in 1,3,10,30 days with speeds (for a 102 kg robotic craft) of about 0.4% the speed of light when used in a “photon rail gun mode”.  Such speeds exceed the galactic escape speed. The same system will propel a 102 kg probe to 2% the speed of light when propelling a spacecraft out to 30 AU after which the spacecraft will coast and will reach 3% c with continued illumination. The same system can also be used for communications out to extremely large distance. For example all the known Kepler planets would see the DE-STAR beacon as the brightest star in the sky (assuming their sky is like ours). The system is also easily visible at intergalactic distances (Andromeda for example) and indeed two such systems could "see each other" across the known universe. This brings up the question of a visible/ IR SETI search that I will discuss along with their implications. Smaller versions of this same system are immediately useful and can be built now.  For example, a DE-STAR 1 (10m size array) would be capable of evaporating space debris at distances up to 104 km away (~ diam of Earth) while a DE-STAR 2 could begin diverting volatile-laden asteroids/ comets that are  100m in diameter by initiating engagement at ~0.01-0.5AU. Other applications we have studied include active asteroid illumination searches and remote composition analysis of the ejected plume my molecular absorption spectroscopy and down linking power to the Earth via millimeter or microwave.  DE-STARLITE is a miniature version of DE-STAR with a power level of 1-1000 kw that is designed to be sent to the target and is dedicated to a specific target (ie standon system). Otherwise it shares the same basic characteristics and technology and laser target physics as the large standoff system. We are in the process of studies for both systems. Most of the core technologies now exist and small systems can be built to test the basic concepts as the technology improves.

     


    Philip Lubin is a professor of Physics at UC Santa Barbara whose primary research has been focused on studies of the early universe in the millimetre wavelengths bands. His group has designed, developed and fielded more than two dozen ground based and balloon borne missions and helped develop two major cosmology satellites. Among other accomplishments his group first detected the horizon scale fluctuations in the Cosmic Microwave Background from both their South Pole and balloon borne systems twenty years ago and their latest results, along with an international teams of ESA and NASA researchers, are from the Planck cosmology mission which have mapped in exquisite detail the structures of the early universe. He is a co-I on the Planck mission. He is co-recipient of the 2006 Gruber Prize in Cosmology along with the COBE science team for their ground-breaking work in cosmology. He has published more than 250 papers.