Donating to Milkyway@home / Příspěvky Milkyway@home

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Donating to Milkyway@home / Příspěvky Milkyway@home

#1 Příspěvek od krahulik »

V srpnu tohoto roku se v novinkach projektu objevila informace, že profesor Newberg prošel všemi nezbytnými kroky k možnosti přijímat dary/příspěvky MW. Napsal motivační dopis, ve kterém popisuje učiněné pokroky ve vědeckých výpočtech a astronomii, včetně finančního stavu projektu.
Professor Newberg has gone through all the steps to allow MilkyWay@Home to actually accept donations and has written a letter of request, which I've posted here. The letter discusses the progress we've made in both scientific computing and astronomy, as well as our current funding situation. You can directly access the page to make donations here.
August 4, 2009
Dear Friend of Science,

If you are receiving this letter, you are probably already donating your computing power to the advancement of science by choosing Milkyway@home in the BOINC infrastructure. Thank you! We are very excited that 28,000 of you have donated your processors to help us discover the spatial structure of the Milky Way, making this our most important resource for this highly computationally intensive task. In this letter we will share with you the progress we have made so far, and ask whether there are some among you who would like to help us with a cash donation so that we can support students involved in this project that will keep the project running through what we anticipate will be a short funding gap in early 2010.

Progress in Galactic structure
With your help, we have made significant progress in tracing the Sagittarius dwarf tidal stream through the halo of the Milky Way. Let us explain what the Sagittarius dwarf tidal stream is, and why it is important. We are only now beginning to understand the process by which galaxies form. The current picture is that galaxies like the Milky Way formed through a “bottom-up” process, meaning that small star clusters and dwarf galaxies formed first. These smaller galaxies merged with each other over time, creating larger and larger conglomerate galaxies. The hydrogen gas in each of these galaxies stuck together, and radiated away energy until it formed a disk of gas in the Galactic plane. Stars like the Sun formed out of this disk gas.
The stars in the outer parts of the Milky Way were actually formed in other galaxies that later merged to make the Milky Way; studying them tells us about the galaxy formation process. What we can see from these stars is that some small galaxies are still merging with the Milky Way even now. When a small “dwarf” galaxy comes close to the center of our galaxy, it experiences tidal forces not unlike the tidal forces that the Moon exerts on the oceans. The dwarf galaxy stars that are closer to the Galactic center are being pulled more strongly by gravity than the stars that are farther away (this is the meaning of the term “tidal force”), and if the difference in force is large enough, the stars get ripped from the dwarf galaxy and start orbiting freely around the Milky Way. By this process, dwarf galaxies are assimilated into the outer parts of the galaxy, known as the “stellar halo.”
Besides telling about how the Milky Way galaxy formed, the tidal debris streams that are formed when stars are pulled from dwarf galaxies can tell us about the distribution of dark matter in the Milky Way. It is thought that 90% of the mass in the galaxy is made of a type of matter that does not interact with light or any other type of electromagnetic radiation. Since we see by light (either objects emit their own light, or absorb or reflect it), we cannot see this new type of matter – thus the term “dark matter.” With ever more powerful instruments, we can in principle learn the position and velocity of every star in the Milky Way. However, the stars in tidal streams are the only ones for which we also know where they were in the past; they were all initially bound to the dwarf galaxy. That makes these stars very important for determining the distribution of mass (and thus dark matter) in the Milky Way.
Interestingly, current models of the tidal disruption of the Sagittarius dwarf galaxy have created a puzzle because no proposed halo shape fit all parts of the stellar data. The results from Milkyway@home may help us to solve this impasse, because we are finding that previous determinations of the positions of Sagittarius dwarf galaxy tidal debris were incorrect. We are also able to make more accurate determinations of the number of stars in the star stream. We expect that our data will result in better models for tidal disruption that give us a clear message about the shape of tidal debris in the Milky Way galaxy. The better we understand the density of dark matter as a function of position in the Galaxy (and currently the only way we have to detect dark matter is by its effect on matter that we can see, such as stars), the better we can constrain theories of what the dark matter is made of.

Progress in scientific computation
In addition to learning about our own galaxy, Milkyway@home is providing a platform for computer science researchers to develop parallel computing, study distributed computing as a platform for scientific computing, learn how to best use the heterogeneous nature of volunteer computing, and create a general-purpose maximum likelihood engine for scientists. Unlike grids and supercomputers, we do not control the work units processed by BOINC volunteers – you all choose to process work units as it suits you, and you have all types and speeds of processors and network connectivity. We continuously work to develop better asynchronous search algorithms that maximize our productivity from your contributed infrastructure.
We have been astounded by many parts of our experience with BOINC. We are impressed with the quantity and quality of computing resources that have been made available to us by volunteers. We have been impressed by the effort some of you have put into re-writing our code to run quickly on your architectures, and by the feedback we get from the user community on our code. One of our users re-wrote our code so that it worked on a GPU, and showed us how much faster our code would run if we had a GPU version. This sparked activity on our side to make this available to everyone. In a way, we are learning a whole new and interactive way to do computing for science projects that was pioneered by the SETI@home application. But as a scientific community we are only beginning to learn how to use the tremendous resources that are available.

Request for cash donations
The event that sparked this letter is that we are finishing our US National Science Foundation (NSF) grant this year, and that grant is the primary support we have for running the Milkyway@home project. Unfortunately, the NSF program under which we were originally funded no longer exists. We have secured funding that will keep us operating as usual through the end of 2009, and we hope that we will again be funded starting in summer 2010, through some new opportunities that we are pursuing. But, there is a gap.
We are hoping that this letter will raise about $30,000 that we need to support this project through the spring 2010 semester. The majority of our costs directly support students who maintain the servers, answer your questions in the forum, create new Milky Way models and improve the computing infrastructure, and create knowledge from our activities. In so doing, they learn how to become the researchers of the future.
Any capital campaign depends on the participation of very many people at very many levels of support. To make this goal, we hope that there will be one person who will be able to contribute $5000, about two who can contribute $2000, several who can contribute $1000, and so on. We also hope that about 200 of you can donate just $25. A small donation may not seem like much, but put together it is as important as the largest donor. This is a concept that must be easy for the BOINC volunteers to understand!
We have made arrangements for the Dudley Observatory to collect donations, though a special website at: ... Home2.html
From this site, you can contribute through a PayPal account or with a major credit card, and the donation is completely tax deductible for US taxpayers. You can print out a receipt from the site, or we will send you a letter of thanks. If you would like to donate by check or other mechanism, that can also be arranged.
For gifts of $1000 or more, you may specify a person, family, or organization to be acknowledged in research publications which come from Milkyway@home research, and we will send you an author-autographed copy of each publication.
Thank you for the overwhelming support you have already given to this project, and we look forward to working with you in years to come.


Prof. Heidi Jo Newberg
Prof. Bolek Szymanski
Prof. Carlos Varela
Prof. Malik Magdon-Ismail
Znění dopisu je dostupné na fóru projektu. Stránku pro darování příspěvku naleznete zde.


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