How Far Away Is It - 05 - Nearby Stars (1080p)
Δημοσιεύτηκε στις 17 Αυγ 2013
Text at http://howfarawayisit.com/documents/
In
this segment of our "How far away is it" video book, we take a look at
our stellar neighborhood and how we know how far away these nearby stars
are.
We cover the first stellar parallax measurement form the
star Cygni 61. Then we examine our stellar neighborhood including:
Proxima Centauri, Alpha Centauri, Barnard's Star with its Proper Motion,
Wolf 359, Lalande 21185, Sirius A & B, 61 Cygni, Altair, Fomalhaut
with its planet, and Vega.
A deeper look into what we mean by
'luminosity' is outlined. We point out that it is measured in watts just
like a light bulb and that its value over distance from a point source
follows the 'inverse square law'. We use our Sun as an example and
introduce Einstein's famous "energy = mass time the speed of light
squared" formula.
We then cover some more stars including:
Pollux, Arcturus, GJ1214, Capella, and Castor. Having reached the limits
of ground based telescopes to measure parallax, we discuss the European
Space Agency's Hipparcos satellite and the more distant stars it helped
fined parallax for including: HD 189733, Aldebaran, Mizar, Spica, Mira,
Polaris, and Antares. Along the way, we cover how a star's mass is
calculated from the motion of binary stars, and then we build the mass
vs. luminosity empirical graph.
We end by pointing out that
parallax only takes us to a small percentage of stars in the Milky Way
and that we'll need to know more about light to go any further.
STEM
In
this segment of our "How far away is it" video book, we take a look at
our stellar neighborhood and how we know how far away these nearby stars
are.
We cover the first stellar parallax measurement form the
star Cygni 61. Then we examine our stellar neighborhood including:
Proxima Centauri, Alpha Centauri, Barnard's Star with its Proper Motion,
Wolf 359, Lalande 21185, Sirius A & B, 61 Cygni, Altair, Fomalhaut
with its planet, and Vega.
A deeper look into what we mean by
'luminosity' is outlined. We point out that it is measured in watts just
like a light bulb and that its value over distance from a point source
follows the 'inverse square law'. We use our Sun as an example and
introduce Einstein's famous "energy = mass time the speed of light
squared" formula.
We then cover some more stars including:
Pollux, Arcturus, GJ1214, Capella, and Castor. Having reached the limits
of ground based telescopes to measure parallax, we discuss the European
Space Agency's Hipparcos satellite and the more distant stars it helped
fined parallax for including: HD 189733, Aldebaran, Mizar, Spica, Mira,
Polaris, and Antares. Along the way, we cover how a star's mass is
calculated from the motion of binary stars, and then we build the mass
vs. luminosity empirical graph.
We end by pointing out that
parallax only takes us to a small percentage of stars in the Milky Way
and that we'll need to know more about light to go any further.
STEM
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