Are there any stars in the sky that we can see the way they were a hundred years ago?

Question

Aude, my 14 year old sister thinks that they are all much further than that,no less than a thousand years away, is she right?

Answer 1

The following stars, all among the 60 brightest in the sky, are given as being nearly or exactly 100 light years away from Earth:

The first column is its ranking in order of brightness, the second column is its magnitude, the third column is its star name by the constellation it is in, the fourth column is its individual name, and the final column is its distance in light years away from us,

59th 2.12 (var) β Per Algol 93
50th 2.04 β Cet Deneb Kaitos 96
54th 2.06 α And Alpheratz 97
32nd 1.74 α Gru Al Na'ir 100
38th 1.85 η UMa Benetnasch (Alcaid) 100
41st 1.90 γ Gem Alhena 100
29th 1.70 β Car Miaplacidus 110
40th 1.87 α1 UMa Dubhe A 120

UMa is Ursa Major, The Great Bear, so next time you look at that constellation, you are looking at events that happened in 1906 on Benetnasch and in 1886 on Dubhe A

Aude might like to find these eight stars for herself? Algol is a famous binary star whose dimmer companion eclipses the much brighter Algol once every 68 hours or so (or did in 1909 of course!) as they rotate around one another, As a result of these frequent eclipses, Algol's magnitude changes regularly between 2.3 and 3.5 over a period of 2 days, 20 hours and 49 minutes.

HOW MANY OF THE STARS LESS THAN 100 LIGHT YEARS AWAY ARE LIKE OUR SUN?

The sun is a G2 Main Sequence star (according to the Morgan-Keenan spectral classification, the way stars are now classified).

There are more G-type stars near us than you might think, As many as 511 or more stars of spectral type "G" (not including white dwarf stellar remnants) are currently believed to be located within 100 light-years of Sol -- including Sol itself. Only around 61 are located within 50 light-years (ly), while some 450 are estimated to lie between 50 and 100 light-years away.

Surprising when you consider that G-type stars make up only 8% of Main Sequence stars,

G Stars within 100 Light-years

Light-years from Sol / Number
0 - 10 2
10 - 20 4
20 - 30 11
30 - 40 10
40 - 50 34
50 - 60 51
60 - 70 59
70 - 80 88
80 - 90 109
90 - 100 143
Total G Stars 511~

Of those five hundred+ G-type stars, astronomers believe that five have evolved out of the main sequence into giant stars, while an additional 78 or so may be subgiants. As many as 19 G-type stars have been identified as being located in Sol's immediate neighborhood (within 10 parsecs or 32.6 light-years). Due in part to their relative brightness and proximity (as well as abundance), many G-type stars can be seen with the naked eye in Earth's night sky.

As of October 2005, astronomers have been able to detect the presence of planets around only 28 G-type stars (including Sol) -- or around 5.5 percent -- of those 511 stars located within 100 light-years of Earth.

About 200 extrasolar planets have now been detected in the Universe, overall.

Answer 2

There are many stars that are closer than 100 light years from us. The brightest star in the sky, Sirius, is only 8 light years away. The closest star to the sun is 4.3 light years away. Other bright stars within 100 light years include:
Arcturus, Vega, Capella, Altair, Aldeberan, Pollux, and Formalhaut. There are also quite a few dimmer stars within that distance including Barnard's star, epsilon Eridani (which has planets, by the way), and tau Ceti (which also has planets).

With that said, most of the stars we see at night are farther than 100 light years away. Almost all that we can see without a telescope are within a thousand light years or two.

Addendum: To the person who claims the Eagle nebula is 750 million light years away; this is clearly wrong! The Eagle nebula is a gasseous nebula witin our galaxy and our galaxy is only about 100 thousand light years across. The true distance is closer to 7000 light years.

Answer 3

It depens on which stars, and how far they are away, this is measured in light years
so for instance, if a star is 500 lightyears away, it takes 500 years for the light produced by the star to reach earth, in other words, we see the star as it was 500 years ago
a lightyear is the distance light has made within a year, with a speed of 300,000 km/sec
so it is certainly possible, if you know for instance that the light of the sun needs 8 minutes to reach us...so we see how the sun looked like 8 minutes ago, when the sun goes down, she actually went down 8 minutes ago
but of course, the sun is very close, the most far object ever seen, is seen as the edge of the universe, and is about 13billion light years away

Answer 4

Any stars that are 100 light years away, we see as they were 100 years ago. But the majority of the stars in the night sky are thousands and thousands of light years from us.

Answer 5

The following site gives details of some stars that are within 100 light years of Earth.

The closest star to Earth is Proxima Centauri (also known as Alpha Centauri C, at 4.22 light years. However this is only a tiny Red Dwarf and is not visible to the unaided eye.

Alpha Centauri A at 4.36 light years is the closest star visible to the naked eye.

If you are looking for a star exactly 100 light years away the nearest candidate to this is the 3rd magnitude star Edasich, or Iota Draconis, which is between 98 and 102 light years away.

Answer 6

The closest star is Alpha Centauri, 4 light years away, so we're seeing it as it was 4 years ago. Sirius is (IIRC) 9 light years away - there must be hundreds of visible stars within a 100-ly radius.

Answer 7

All stars (except the sun) are much, much farther away than one hundred light years. So, the answer is no, you cannot see any star as it was 100 years ago.

Answer 8

it all depends on how far away the star is. as light travels at a certain speed, to travel long distances requires a lot of time. therefore the light from the stars that are further away is "older" than the light from closer stars.The closest star is 4.2 light years away so we would be seein the star as it was 4.2 years ago.

Answer 9

Light travels at 186,000 miles per second. The closest star, Alpha Proxima is about 25 trillion miles away, or about 4 light years (the distance light travels in one year)

The sun is about 8.3 light minutes away.


The FARTHEST star you can see with your eyes is about 2.6 MILLION light years away. The light you're seeing from it is around 18 billion years old

Answer 10

All galaxies are much further away but the nearest stars in our own galaxy are only a few light years away (closest is just over 4ly).