# The Most Mysterious Object in the Universe – by Physics Girl

Physics Girl astrophysics series – Brown Dwarfs are among the most recently observed objects in the universe. They have at MOST 8% the mass of the Sun. The lower mass boundary is not known! So they are halfway between stars and gas giant planets. Astrophysicist Daniella Bardalez Gagliuffi sits down with Dianna Cowern to discuss the latest research and the history of Brown Dwarfs Continue reading

# Using Parallax: How Far is that Star?

## Introduction

Since the distances to the stars cannot be measured directly, astronomers use a variety of techniques including triangulation and parallax, comparison of absolute and apparent magnitude, and Cepheid variables. Continue reading

# Teacher Demo: Bright Star or Close Star?

When you gaze up in the night sky, some stars will be very bright while other stars are barely visible to the unaided eye. With the aid of binoculars, you may be able to observe different colours in the stars. The brightness and colour of a star depends on three factors: temperature, distance, and size.

There are two measures of how bright a star appears:

• The “apparent magnitude” of a star describes how bright the star appears from Earth. This scale ranges from the brightest star in the sky, the Sun, which is set at –26.8. The dimmest stars, which are only visible with the largest telescopes, have an apparent magnitude of 25. The faintest stars visible by the naked eye have an apparent magnitude of 5.5. A decrease of 1 on the scale represents a 2.5 times increase in the apparent brightness.
• The absolute magnitude of a star is the measure of brightness of a star if it were at a distance of 32.6 light years (ly) from an observer. By placing all stars at this distance, the true brightness of the stars can be compared.

We know that the apparent magnitude of the Sun is the brightest at –26.8. However, when using the absolute magnitude scale, the Sun would be barely visible to the naked eye, with a reading of 4.8.

# The Evening Sky Map — Best Bargain In Town

To help find your way around the night sky, Skymaps.com makes available for free each month The Evening Sky Map. It is a 2-page monthly guide to the night skies of the northern and southern hemispheres. Each issue contains a detailed sky map, a monthly sky calendar, and a descriptive list of the best objects to see with binoculars, a telescope, or using just your eyes. The font size on the printout is about a nine, but still readable for my aging eyes.

Great magazines like SkyNews (Canadian) and Astronomy (American) offer an equal amount of information as Skymaps and with interesting articles that befit magazines of this caliber.

Educators can make printed handouts for non-commercial educational use.

For educators and students who want a current sky map for free, this is one valuable resource.

The above Skymap is used with permission.
See http://skymaps.com

“Your sky maps are great — visually attractive, easy to use and information dense. Great for unaided eye and casual stargazing, a fine introduction to astronomy, especially for younger night sky explorers. Great job! Thanks!”
— Kevin M. Ahern (Massachusetts, USA)

“Great maps. I am so happy to have found you. Thank you. It helps so much to have a monthly map, for planets and such-like and rediscovering childhood constellations with my child.”
— Monty Drake (British Columbia, Canada)

By Stan Taylor
Stan Taylor is a retired elementary school teacher. He currently does science workshops for Scientists in School and is a member of the Crucible and Elements Editorial Committee (CEEC).

# How do you measure the distance to a star?

How do you measure the distance to something so incredibly far away light a star?  As you’ll see in this video from Scientific American, the math involved is actually quite simple and relies on a property called parallax. Click here to have a look.