Yes and no.

Yes (mostly) - the time, in absolute terms that the earth takes to complete one lap around the sun has been close to the same. Orbital period is determined by an objects distance from the sun. The Earths average distance from the sun has been basically the same since its formation, meaning its orbital period has been the same.

No - We typically measure years in number of days (roughly 365.25 right now) it takes for the Earth to complete one orbit. While the overall length of orbit in say, seconds has not changed, the number of days it takes HAS because the Earths rotation is slowing down. Billions of years ago it probably took less than 20 hours for the Earth to complete one rotation, aka one day. So the number of "days" in the year was greater, as each day was shorter.

So in raw time, yes, its basically the same. In terms of how many "days" it took? No, it used to be longer.

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Year is what we define it to be. For us as humans it was easy to set a year relatively to the cycle of seasons. Only later that we found out that a year is how long it takes for the earth to go around the sun.

So you see, every planet has its own year, its own orbital period. Venus year is 255 earth days, what with it being closer to the sun.

Neptune being so far, it's year is as long as 165 earth years.

The reason we look at the age of the universe in time relative to us – to the earth year, is because it's much easier to conceptualize it, instead of spending time inventing a new unit of time.

Even speed on a galactic level we measure in the distance light travels in an earth year.

So, was a year different in different times?

actually... yeah, though not how you might think. Different calendars had slightly different day counts for years. For instance, old persian calendars had 360 days in a year. The old roman calendar – before the introduction of the Julian calendar was 304 days long. When transitioning to the Julian Calendar there was a transitional year with 445 days.

But when speaking of age of the universe, people refer to it as it is today – 365 days per year –> 24 hour per day –> 60 minute per hour –> 60 second per minute. a Second scientifically defined in relation to the frequency of a caesium 133 atom.

So the year one of the universe, is the same year you expirience today.

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I'm assuming you are talking about the orbital period of the Earth? Years do change as we change definitions of time, although these are small.

The Earth is actually moving very slowly away from the Sun, so years are getting a little longer, although the difference is pretty difficult to measure.

The Sun pushes the Earth away due to the solar wind, but this actually has very little effect. More important is the mass loss by the Sun via the solar wind (and fusion reactions). The Sun loses a mass of about 8 Earths per year. One site I saw said this has resulted in a net loss in velocity of 22 m/s over the life of the solar system--fairly insignificant to the current 29.78 km/s

If you go back far enough, then the Earth was involved in major collisions. These could have had great effect on the orbital period by (mostly) adding large amounts of mass.

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Time is a human construct. We have named a year to be the time it takes for 1 orbit of the sun. However every planets orbit is different in duration. Hence a "year" is different depending on what planet you are on. So say an orbit for a planet is 100 years in the way we look at time then the universe to them would only be 138 million "years" old.

You also need to remember that when we started keeping track of days and hours it would have been possible to break them up differently than we did. We could have had days with 57 "hours" in a day, 10 "days" to a month and so on.