Vũ trụ là toàn bộ hệ thống không-thời gian và được cấu thành bởi nhiều hệ Siêu thiên hà. Mỗi một hệ Siêu thiên hà lại bao gồm nhiều hệ Thiên hà.Hệ Thiên hà mà trái đất chúng ta đang tồn tại được gọi là hệ Ngân hà (Milky Way).
Nhìn lên bầu trời đêm ta thường thấy những vết trắng mờ mờ như sữa. Đó là các thiên hà xa xăm. Theo tiếng Hy Lạp “galaxy” có nghĩa là sữa. Từ lâu người ta đã chú ý đến một dải trắng như sữa vắt ngang bầu trời đêm và gọi đó là con đường sữa (Milky way), hay tiếng việt là Ngân hà. Đó là thiên hà đầu tiên được con người biết đến và có chứa trái đất chúng ta.
In our quest to elucidate the origin of the universe and the formation of
galaxies, particularly that of the Milky Way in which we live, astounding
progress has been made in recent years through observational and theoretical
studies. Not only have gigantic surveys covering a large fraction of the sky
brought statistics enlightening evolutionary paths of galaxies, but powerful
instruments, such as radio interferometers and ground- and space-based optical/
infrared telescopes, have been able to map individual objects with high
sensitivity and spatial resolution.
Dust is a ubiquitous feature of the cosmos, impinging directly or indirectly on
most fields of modern astronomy. Dust grains composed of small (submicronsized)
solid particles pervade interstellar space in the Milky Way and other
galaxies: they occur in a wide variety of astrophysical environments, ranging from
comets to giant molecular clouds, from circumstellar shells to galactic nuclei.
The study of this phenomenon is a highly active and topical area of current
In 140 A.D. a Greek astronomer
named Ptolemy wrote that the
Earth was the center of the
universe. He thought all the stars,
the Sun, and the Moon revolved
around it. This made sense
because that is how things looked
in the sky from Earth. We call
Ptolemy’s theory the geocentric
view. It is derived from geo (Earth)
and centric (center). Astronomers
believed the geocentric view for
1,500 years until 1543.
The Heliocentric View
About 500 years ago,
Copernicus found that the Earth
and other planets revolve around
the Sun. His theory was published
The Local Group of Galaxies is the small, loose cluster to which our Milky Way
Galaxy belongs. It consists of approximately 36 known members, most of which are
dwarf galaxies. This Atlas includes identification charts for 32 members for which
identification atlases have not hitherto been published. There are numerous atlases of
various sorts for the Milky Way Galaxy and there is a published atlas for M31 and its
two close companions, M32 and NGC 205 (Hodge 1981). The Magellanic Clouds
have also been covered by identification atlases (Hodge and Wright 1967 and 1977).
(BQ) Ebook Space and technology: Inner and Outer Planets provides about what are some differences between inner and outer planets? How were Mercury’s craters made? Why will astronaut's footprints remain on the Moon’s surface for years?.
Nature has a rather splendid way of impressing us. There are few who have
not been overwhelmed, time after time, by a sense of awe at the beauty of a
glorious sunset, the sight of distant mountains shrouded in a soft blue haze
of mist, or the brilliance of a starlit night. As a child, I found myself fascinated
by the mysterious patterns of the constellations, the faint glow of the
Milky Way, and the slow movements of the planets across the night sky. I
devoured books on astronomy and even managed to build a small telescope
to study the sky in greater detail. It allowed me...