SCIENCE-SUPPLEMENT 



SCIENCE SERVICE NEWS BULLETIN 



Science Service, Washington, D. CA 



HELIUM HUNTING IN THE MILKY WAY 



By Isabel M. Lewis, 

 U. S. Naval Observatory 



Helium, our wonderful non-inflammable balloon 

 gas, does more than lift airships ^vithout danger 

 from explosion. Mueli is being learned of the 

 size, structure and form of the universe by a 

 stud}' of the stars containing incandescent helium. 



Stars of the helium type give light which when 

 broken up by the spectroscope shows prominently 

 the bright yellow lines of helium, indicating that 

 fthis gas is present conspicuously in their atmos- 

 phere. They are excessively hot and massive and 

 bluish-whiite in color, and they occur in abundance 

 — often as double, triple or multiple stars en- 

 meshed in nebulosity — in the constellation of 

 Orion. Hence their name of Orion stars. 



It was found some time ago that comparatively 

 near us in space, that is, so near to our solar 

 system that light traveling 186,000 miles per sec- 

 ond w-ould only take a few hundred years to 

 reach it, there exists a local cluster or group of 

 these helium stars in the constellation of Orion. 

 In fact, our sun is a star in rthe Milky Way and 

 within this extensive group. It is about fifty light 

 years to the north of the central plane of that 

 great galaxy. 



Enormous dark tracts of nebulosity in that 

 ithickly s.tar-iS.trewn space, located in the constel- 

 lations of Centaurus ■ and Scorpio and shutting 

 ofE light from stars beyond, lie between 650,000 

 and 975,000 light years from the solar system. 

 This is about the greatest distance that has been 

 found for any type of celestial object and shows 

 how enormous is the extent of the Milky Way 

 along its greatest axis. 



Because all the helium .stars in the Orion group 

 are well within the range of vision of the naked 

 eye or art most no fainter than stars of the 

 seventh magnitude which lie just beyond the 

 naked-eye vision, it was assumed that there were 

 few, if any, fainter helium stars lying beyond this 

 group. 



Eecent investigations made at ithe Harvard Col- 

 lege Observatory and based upon daita furnished 



1 For a statement concerning Science Service 

 and the reasons for printing its 'news bulletins in 

 this place, see the issue of Science for Novem- 

 ber 24. 



by the new Henry Draper Catalogue, however, 

 reveal that there are many faint helium stars be- 

 yond and independent of this local group. These 

 fainter stars are confined closely to the vicinity 

 of the Milky Way, lying within a belt only ten 

 degrees wide on either side of it. Some of these 

 stars must be at distances of thousands of light- 

 years from the earth. It has been found also 

 that the distribution of helium stars is not uni- 

 form along the Milky Way. In some regions they 

 are grouped more densely than in others and the 

 southern sky is particularly rich in stars of this 

 class. 



Just as the Columbuses and Magellans by 

 means of their ship^ made voyages into the un- 

 known regions of our earth and brought back 

 new knowledge of the size and shape of the world 

 lOm which we live, so these explorers of the skies 

 with their spectroscopes seeking out the helium 

 stars are adding to our knowledge of the star-lit 

 universe of which our planet is a part. 



NEW MUSEUM INTERPRETS AMERICAN 

 ABORIGINAL LIFE 



New light from all directions breaks in upon 

 the life of the aborigines of the Western World 

 through the study of the vast collections of the 

 Museum of the American Indian, Heye Founda- 

 tion, New York, which was opened free to the 

 general public November 15. 



This is the only museum in the world devoted 

 exclusively to the preservation of the records of 

 the races which were living in the Western World 

 when Columbus reached these shores, and con- 

 tain 1,800,000 specimens. The great problems to 

 which it is dedicated include the unveiling of the 

 mystery of the origia o>f the so-called Bed Men 

 themselves. It is within the range of possi- 

 bility, in the opinion of George 6. Heye, the 

 founder of the museum, that this goal will be 

 reached. 



The building of the Museum of the American 

 Indian is situated in Broadway at 155th street, 

 close to the museums of the Hispanic Society and 

 of the American Numismatic Society and the 

 quarters of the American Geographical Society. 

 The rearing of the whole important group was 

 due primarily to the zeal of Archer M. Hunting- 

 ton, who gave the site for the Museum of the 

 American Indian and as one of its trustees gave 

 liberally to its building fund. 



